What Pontiac is this horn button from?

[G-Body_Vet]

What is this from and what style wheels will it fit? I'm guessing it would fit the MC SS style wheel and the older Chevy 4 spoke that came in 70's Chevelles & Novas. I can't think of any Pontiacs this would have been on. The diameter looks too small to fit the mid 70's GP's.

 

[RegalBegal]

If I'm not mistaken, that belongs to a Pontiac Astre (Chevy Vega).

 

[81X11]

My guess is Pontiac T1000.....aka Chevette

 

[Phoenyx]

My guess is Pontiac T1000.....aka Chevette

x2 been in and seen many of those.