Yeah, those "improvements" are hell on luthiers and anyone else trying to separate neck and pot for any reason.
In what year was this advertisement printed? I used to have a Clifford Essex Imperial made before the WW1 ("The Great War) that had these screws or nails or bolts. What a pain. It was a good sounding banjo especially with a natural vellum and a two footed bridge made from Osage Orange wood.. A lucky student of mine has it now. I told him that I'd sell him the banjo on the condition that if he ever wanted to change the bridge that he give the Osage one back to me.