Well, unless someone comes up with more information, we seem to be at an impasse with the round and "Art Deco" horn buttons. I for one, like both of them, and it looks as if both are acceptable on my '55 2nd. Not that I would ever presume that my truck is anywhere near original, I have tried to keep its originality intact as much as possible. I am fortunate to have both types, and switch them out from time to time! (this guy has waaay to much time on his hands) Thanks all for a "Beerry intressting" discussion.