Is there any evidence for that? When those wheels were used on what has been an issue for argument as long as I can remember (but I thought needlessly so). Brochure art was the genesis of the consternation, I thought, showing the 79 wheels in the 78 preproduction brochure.
I have the 78 car distribution bulletins and a bunch of parts books, and I never found any hints of a except that it has to be late. There is a car distribution bulletin about it, for clarification (not a change), dated march 9, 1978. This bulletin says the ws6 wheel "is painted solid gold including the ribbed edges. The 7" cast aluminum wheel has silver polished ribbed edges rather than being painted solid gold." That's getting reasonably late. They weren't too brilliant with choice of words either.
That's the last bulletin I have, and naturally, I don't know what I don't know. I don't have the 79 bulletins, and I might be missing the proper 78 one.