I have a Henry L. Mason guitar. It’s an acoustic archtop, build in 1938. Henry L. Mason was a guitar builder for Gibson. Some of the workers were allowed to build there own guitar as a sort of annual bonus. They could use materials and tools from the Gibson Factory. My guitar was bought during WW 2 in Europe (holland) and migrated with it’s owner Frank Zegveld to Melborne, Australia. I used to play it when I was there in 1981 and some 10 years later I inherited it. Ps Frank’s still alive and well but gave me the guitar anyway…..