I found the curiosity pictured above at my local Goodwill a few weeks ago. At first glance, I thought it was make-believe — someone’s fantasy of what Olde Tyme furniture should look like. But soon, three things became clear.

One, it was expertly made with fine materials. Two, it was part of a tradition: As a bit of Googling revealed, lyre-base card tables have been a thing since the early 1800s. And three, it was old.

The question was: How old?

This month, we’ll learn a few ways to tell whether a piece of furniture is a genuine period antique, a nice reproduction, or a poor imitation. To do it, we’ll be looking at a style of furniture called Country Sheraton. Named for the British author Thomas Sheraton (1751-1806), who wrote numerous influential books on cabinetry, the Sheraton style was hugely popular in the early years of the United States, and it never completely fell out of favor. (The New York Times arts critic Walter Rendell Storey reflected on its enduring appeal in 1927.)

Country Sheraton is the vernacular American version. Small-town artisans simplified the original form, doing away with carved details and exotic veneers and favoring native North American woods like rock maple and black cherry. When you think of “farmhouse” furniture, you’re probably picturing Country Sheraton or one of its many descendants.

Two centuries of popularity means you’ll run into a lot of Country Sheraton-style furniture at antique shops, so it’s perfect for studying the differences in form, construction and materials that distinguish period pieces from reproductions.

I found the four examples below on local listings and at secondhand stores. None cost more than $40. One of them is period Country Sheraton from the 19th century. The rest are from the mid-to-late 20th century. Before we look at the telling details, can you tell which is the oldest?

If you chose the small table with the scroll back (no. 3), congratulations. It was probably made between 1820 and 1850. I estimate the desk (no. 1) is from the 1940s. According to the seller, the tall stand (no. 4) is from the 1960s. The short stand (no. 2) is 1980s Ethan Allen.

Here’s how I confirmed the scroll-back table was genuine. You can look for the same clues on almost any style of European or North American furniture.

The Dovetails

If the piece in question has a drawer, pull it out and look at its construction. Drawers have been held together with dovetailing for centuries, and even today it’s the best method: Unlike glue or nail joints, dovetail joints don’t come apart when yanked. But the way dovetails are made has changed over the years, and that makes them a good first indicator of the age of a piece.

Until the mid-19th century, dovetails were hand-cut, so they showed variation. And they were highly asymmetrical — delicate vees locked between broad ones. After that, machine tools were increasingly used to produce uniform and similarly proportioned dovetails.

The Hardware

The Country Sheraton table’s top, back and shelf are held on with square-cut nails. They’re the oldest form of machine-made nail, dating to the late 1700s. Modern nails are formed from lengths of wire, giving them a round head and cylindrical shank. Square-cut nails are still produced and often used for historical effect on reproduction furniture, but the rustiness of my table’s nails and lack of any modern fasteners elsewhere suggested they were original to it.

Screws are as venerable as square-cut nails, and until the early 1900s, almost all of them were the simple slotted, or flat-head, type. More advanced designs, like Phillips-head screws, came later. Slotted screws can help date a piece. In particular, screws made before 1850 often have irregular slots, since they were still being hand-cut.

The corrugated fasteners (a.k.a. wiggle nails, shown below) were in the desk from the 1940s, but they didn’t necessarily mean the desk was. As I learned, fasteners of this design go back to the mid-1800s, but were in wide use for several decades starting in the 1940s.

One thing you shouldn’t rely on for dating a piece is its knobs or handles. Replacing them is a cheap way to alter the style, and people have been doing it for ages. The Country Sheraton table came with Victorian cut-glass drawer pulls. I replaced them with brass knobs.

The Honest Signs of Age

It’s not hard to make a piece of furniture look old from six feet away, but it’s almost impossible to pull off at six inches. Cozy up to the object of interest and peer closely.

The period Country Sheraton table is full of authentic grunge — the kind you can’t fake — especially in the whorls of the scroll back. I’ve actually cleaned them up a bit; when I found the table, they were crammed with hard brown wax, probably the remnants of years of regular polishing.

Dirt accumulates naturally in the corners and tight spots of furniture, which is why the maker of the tall stand from the 1960s stained the inner surfaces of the decorative beading on its legs. From a distance, it looks like genuine age. But up close, the illusion is obvious.

Genuine wear and tear is also hard to fake. Here are four signs that it’s been simulated:

• Saw marks everywhere. You wouldn’t accept saw damage all over your brand-new dining table. Neither did your great-great-great-grandparents.

• Heavy verdigris (turquoise-colored corrosion) on brass hardware. Natural verdigris results from the long, undisturbed corrosion of copper by atmospheric acids and precipitation. Brass hardware on furniture typically ages to a dull brown with brighter areas where hands touch it frequently.

• Fake stains around fasteners. Black iron staining is a genuine phenomenon, but tends to occur irregularly. Look closely at any piece with iron staining around every nail and screw; if it appears brushed on, it probably is.

• Flyspecking. That is, finely splattered paint or stain. This is done, depending on what you read, to mimic actual fly droppings (like you’d see on a literal barn find), or just to break up the monotony of a perfect factory finish. Either way, it’s a dead giveaway that a piece was made after 1970 or so. The 1980s Ethan Allen table has it.

With all this in mind, what do we think about that lyre-base card table from Goodwill? After bringing it home I examined it closely, then carefully took it apart, certain I would find proof that it was a reproduction. But the evidence kept pointing in the other direction.

A large bolt holding the lyre to the base looks handmade, as do the brass hinges of the folding top. The screws resemble examples in a Boston Museum of Fine Arts monograph on early North American screw making. Damage to the table is what you’d expect to see on an old piece: The table leaves have split with age, and there is extensive chipping along the front of the base, right where brooms and vacuum cleaners would hit it.

I asked Tom Johnson, a master furniture restorer and YouTube teacher, to check my detective work. His assessment: It’s period American Empire, circa 1830-1840.

Veneered in mahogany and rosewood, with a serpentine top and ogee apron, the table is a wonderful example of fine 19th-century cabinetmaking. The thing is, I don’t want to live with it. In his classic “American Antique Furniture,” Edgar Miller writes of a similar card table that “the charm of the Sheraton style has wholly disappeared,” and I couldn’t agree more. So I’ll find it a home with someone who loves it, and keep hunting for something that I do.