It’s ubiquitous now, but was any mob boss called a “Godfather” prior to the book and movie? Not a definitive source I know, but Joe Valachi doesn’t use the term anywhere (afaik) in The Valachi Papers, and he would know. As a bit of a vintage gangster buff I find its overuse a little annoying.
I just looked- Valachi said that during his initiation ceremony he was given a “gombah”, Joe Bonnano, who he said was kind of his godfather. So he was a regular godfather, not Valachi’s boss, and not even in Valachi’s family (again, afaik). He may have used padrone, but I don’t recall.
If he was “kind of his godfather” then he wasn’t “a regular godfather”, at least in the religious sense. The religious sense gets widened into what would in the US be called a “mentor”, though - which IIUC is what Valachi is talking about, as well as what that 1963 transcript talks about.
And what family are you talking about, biological or criminal? The first isn’t any kind of requirement for a godparent-or-mentor; the second sounds strange.
“Goombah” is derived from the southern Italian cumpa/cumpari, which is in turn derived from compare, which refers to the godfather/godson relationship. Now it generally refers to any friendly relationship (although it is also used derogatorially to refer to Italians).
Valachi seems to have been using it to refer to a godfather like relationship, even if this person might not have been his actual godfather in the religious sense.