What you have here is an Epiphone MM30 made overseas, likely no more than 30 years old. /topic/49639-epiphone-by-gibson-headstock-sheraton-owners-club/) on the Gibson forum suggests that guitars with the "Epiphone by Gibson" headstock logo were made at the Samick factory in Korea between 19. Contemporary logos just say "Epiphone" or "The Epiphone." No "by Gibson."... That can't be the mandolin your friend was given in the thirties.
Regardless, continuing to start multiple threads won't make your mandolin older than it actually is.
You might ask him to clarify HIS age when he received the mandolin because that already might begin to unravel the puzzle.