Gibson J-55 (Jumbo 55) (1939 - 1943)  In 1934 Gibson introduced the first jumbo flat top which was called the Gibson jumbo, this guitar led to the Gibson Jumbo 35 (J-35) in 1936, the J-35 then was replaced by the J-45 in 1942. (adsbygoogle = window.adsbygoogle || []).push({}); While these historic Gibson guitars were making history, in 1939 they also introduced about 400