Gary,
A good place to start your search would be Bruce Berghoff, fellow member and restorer of just these sorts of parts. He routinely runs an add in the Self-Starter, and his Email is
berghoff@chartermi.net . Got my 37 hubcaps from him after sending mine back to him and coming to the conclusion that they were basically un-restorable. Also had him restore my bumper plates and center emblems. Nice work, and you are dealing w/ someone that is very knowledgeable.
BTW, I would refer to these small hubcaps as "Baby Moon" style as distinct from full wheel (Disc) covers. Though the cars often came w/o them, I think the addition of "Trim Rings" (available from Kanter) makes a great combination w/ the small hub cap. To my eye, the small hubcaps w/ trim rings look better than the full wheel covers which were a more expensive option.
Mark Lowery, CLC #25216