I have a junkyard horn that looks slightly better on the inside than yours. I bought it on ebay just to get the bent bracket to mount the other "good" horn on the exhaust manifold.
I have the same interest as you, now. From the outside, it looks like it spent 50 years at the bottom of a lake.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)