I think most owners that might have an extra cap, won't sell because these are known to develop cracks in the center plastic, so they keep a spare. Back when I had my perfect cap on my 68, I had a spare that did have a crack. Today, I would have kept it, back then I resold it. No one makes them, and highly unlikely anyone ever will. Good luck in your search. Is there something you don't like about the 67 factory wheel and button? (I don't know what it looks like)
Yea i had a few and sold them to help fellow buick guys i their restos,i cant take this stuff with me,yea the stock 67 wheel is disgusting and never cared for it
This complete wheel listing ended, but doesn't say "sold". You might consider contacting the seller and make him an offer to sell the horn cap separately. However, zooming in on the close up of the cap shows it to have a lot of defects in the metal surfaces.
