I have a pair of Caymens, and the rivets have sticker on them on the outsides only. They're some kind of plastic thing and you wouldn't necessarily know they're just stuck on, but on the first day I wore them all day at work, I found one of them on the floor. I sit with my legs crossed a lot, so the rivets rub again the seat of my chair, so I think that's why it came off. The other one is still on. I don't think I'm going to try to put it back on again, though. Not worth it since it would probably just come off again.
I think mine were made in Canada, and there's also the word Crocs embossed on the back strap of each shoe.