Although Harmony Guitars was originally established in 1892 in the U.S., any Harmony guitar that has that phrase, "est. 1892" is actually an Asian-made guitar. In the 1970s, the company name, Harmony, was sold for use on Asian produced guitars, shortly after the American Harmony Guitar Company ceased operation. There are distinguishing features for both the American- and the Asian-made Harmony guitars that allow for easy identification. Stella and Sovereign guitars were also made by the Harmony Guitar company and many of those models were then transferred over to the Asian market.
Check the headstock where the name "Harmony" is embossed. If the words "est. 1892" are located under the word "Harmony," it is an Asian-made guitar.
Find the date stamp on the inside of the guitar. This is usually located inside the sound hole or cutaway. Some models have it stamped on the inside of the top of the guitar, near the neck. You will need a small mirror to locate the stamp if this is the case. The older Harmony guitars have a date stamp. An example would be "F-64," or "S-56." The F or S are believed to stand for Fall or Spring, indicating the time of year the guitar was made. The number would be the last two digits of the year the guitar was made, such as 1964 and 1956 in this example. If the date stamped is before 1975, it is most likely an American-made guitar. If it is after 1975, it is an Asian guitar.
Look at the shape of the guitar. An archtop, or guitar with a slightly domed top, will be an American-made guitar. The archtops were never made in Asia, only the flat-top guitars. The dreadnought is a very standard acoustic shape, with the gently sloping curve in and out of the waist of the guitar. Many guitars with this body style were made in Asia as well.
There are several websites that are dedicated to Harmony Guitars, the company and the instruments. Quite a bit of research has been done on the various kinds of guitars and when they were made. Harmony Guitars was a major producer of guitars for many years, so they are not an uncommon find but people who play them are very dedicated to the brand.