The rivet is just to lock the system together. It drops in a hole you drill & the clamp goes over the top. I think you'll be fine w/out it & the RTV.I just got a TRS Yosh pipe and I see in the instructions there is no mention of applying hi-temp RTV at the joints? Won't it leak? And it talks about installing a locating rivet? What is the point of that? I don't have the rivet.