This is the riveted piece. It holds the license bracket to the bumper.
The piece I need is painted black. I is GM # 3857012. A google search for that number shows a bunch of purses, etc. If necessary, they sell the set of 5 for about $150.
On closer examination, it is possible this might fit. It doesn't look like the catalog picture, so I will wait until I am ready to unwrap the bumper and be sure.
You know I had to go out and unwrap the bumper. I was right in the first place. The riveted piece is for the license bracket, so I still need that 5th center bumper bracket.