Serial number records exist for instruments built before 1975 and after 1980. There are several sites that offer serial number look ups. In general, rare guitars are worth more money, and that particular model is valued at between $250,000 and $310,000. If, for example, you have a Gibson Explorer that was made from 1958 to 1959, you have one of the few models produced in that period. A “KC” prefix was introduced on Korean-made instruments in 1997, designating instrument made in Korea at the Cort factory. I’ve looked inside and the label says Anne 1982. This would be a good time to note that some models, particularly 1962 -'65 models, had the serial number embossed on the headstock in lieu of a label. It is a Chinese Harmony, and you recently acquired it, so frankly, it is 'worth' whatever you paid for it. Hofner serial numbers 1975 to 1986 - Serial Numbers 75-86.

What is my guitar worth by serial number 801000-812838.