It probably was barely drinkable back then. But as long as it was sealed it wouldn’t go “bad.” Of course, it wouldn’t age either. It needs to be in a cask for that.
Are you and others here on FR mistaking “bootleggers” for “moonshiners”?
Bootleggers smuggled in the “real” stuff, while moonshiners made their own, which was sometimes dangerous to drink.
JFK’s father was a bootlegger who smuggled good stuff into the US from Canada and made tons of $$$.