I just bought a set of wheel covers to have as spares and found there was a difference in real life I didn't notice in the pictures. The center emblems in these new spares were only about half the diameter of the ones on my car -- which I believe are proper for the car.
Anybody know what the real application for these "small emblem" disks is? That's the only difference in the entire cover. The stainless disk and the cast "hub" are the same, except that on the originals there are two small holes drilled in the middle of the disk to attach the larger emblems. The smaller emblems fit perfectly in the center of the cast hub, and are held in place by the disk from the back. So no extra screws are used or needed. Here's what they look like (top is replacement, bottom is what's on my car):

 

Those are OEM PO-3 caps from a 63 Starfire, these came on my car.

 

Awesome, Don. Mystery solved -- simple difference between '63 &. '64. Three of mine are gorgeous and one was funky, so I got a spare set to restore one and get a perfect 4th. As you might be aware, once a stainless disk get bunged, it's pretty tough to straighten it out due to the retaining ring on the back.
Thanks for the input....
Also, judging by your picture and my spare set, it appears the '63s had a black background in the turbine portion, whereas the '64s had a silver background.
John