I think you're right. There's no ridge, but the spokes aren't as flat as a G/T. I always thought the cast centers were the same, but they're not. The only S/S wheels I ever owned were sold on the car 40 years ago.
Here's a link to some NOS S/S on feeBay. They look identical to matthon's. NOS Vintage 1969 Cragar SS 15X6 Chrome wheels. Mint condition with caps Ford 4.5 | eBay
