I wanted to rivet on the rear bumper bracket as original and bought the reproduction rivets. They did not work for me because the top of the rivet you peen over was too small in diameter, would not fill the hole after peening. I made up my own, plated them dark phosphate, and installed them with an air hammer using a long punch. Here is a drawing of the rivets for future use and a picture of them installed. My originals did not have rings on the head like reproductions do and were dark phosphate.
I did not have a picture of the original rivet peened area so I am not sure what it looked like. George