These Epiphones were thought to have sometimes been built with different species of woods from the original Gibson versions some players speculated that this resulted in the instruments bearing a visual and ergonomic similarity to the Gibson originals but having a slightly different tone however this has always been suspected to be based on prejudice more than empirical fact. The brand was primarily used to issue less expensive versions of classic Gibson models, in a manner similar to that of the Squier brand by Fender. Thus, a Korean-era solidbody Epiphone would have been built under license. One of these contractors was Samick, which also built instruments under license for other brands and in its own name.
From the 1980s, Epiphones were manufactured mainly in Korea but also in Japan by contractors licensed by Gibson. In the early 1970s, Epiphone began to manufacture instruments in Japan. I don't know the years but here is the serial info from wikipedia:
