Which Pony Mags- the ones with black centers or the ones with red centers? The black centered ones were available for the '71-'73 model years, while red center caps were options for the '74-'80 model years.
I have a set of the black centered Pony center caps but they won't bolt onto the factory mags I have- the black caps are a bit smaller.
In any case, it's cool to have them!