Folks - Thanks for the feedback. You were both right on about the clips being rivetted and not welded. The 3600 series caps that I was looking at are, in fact, too large for the 7 1/4" diameter I need to fit onto the 6-clip arrangement that's on my wheels, so I had to pass up that deal. Also, I suspect you were both right about the wheels being off a GMC and not a Chevy. My wife and I have not yet figured out how to attach pics to a Page posting so I can't do that at this time. However, I can attach pics to emails, so I could sent one out that way if you thought it would help ID the wheels. Frank, you OK with that? (Frank - we have a vacation home on Lake Wallenpaupack and plan to move up permanently in about 18 months. I may get a chance to meet up with you one of these days.)