Rivets for fiberglass

I need to repair a few places on the fiberglass of the truck we bought. What type of rivet gun do I need, and what's the name of that thing that rounds them off lol.

Also, where's the best place to purchase them?

Thanks

 

Ok, will do. It has some rivets on it from the previous owner but didn't see any in the local auto store. I'll call some of the body places. Thank you!

 

The previous owner did a good job with them after one of drivers tried to take off part of the fiberglass via a pole. He missed a spot and want to secure it. Just want to get the right ones so it doesn't look like a trashy patch job lol.