The John Wayne reference was around when I was in the Marines long, long ago. John Wayne is the quintessential tough guy and therefore use in the Marines, perhaps other branch's too.
As a side not a "John Wayne" is a P-38 can openers that use old schooler used, when they had C-Rats.
I still have a number of these unopened somewhere and the original one I carried on my dog tags is still there.
On the movie, since R. Lee Ermy was a real life drill instructor I can say the FMJ has the closet thing to REAL boot camp ever put to film. It's an excellent film.