Here's a comparison of the rivets you can get off of Amazon for GM "NOS" v. the ones from ECS.
The ECS rivets are on the top and right in the photos. The Amazon ones have a thicker base than the ECS. Additionally, there appears to be some aging on the ECS rivets, FWIW while the GM "NOS" appear fresh.
The ECS rivets are on the top and right in the photos. The Amazon ones have a thicker base than the ECS. Additionally, there appears to be some aging on the ECS rivets, FWIW while the GM "NOS" appear fresh.