Re: 1967 starcraft falcon 14ft.
Sorry, I should have been more specific. Do you know who manufactured the wheel? You may need to remove it to see inside the back of the wheel's hub. It's probably labeled.
My suggestion would be to measure the diameter of the hole, and get something off ebay that fits. If you buy a smooth/flat center cap, you could get have a vinyl wrap place make you whatever a small piece of vinyl to apply to it.
Occasionally a center cap w/ the Starcraft double SS logo pop up on fleabay too.
Is the hole for the center cap perfectly round? In your pix it looks slightly oval'd