I can see no reason why a snap ring of the correct diameter and thickness would not work in place of those hard to find/awkward to install original clips. A snap ring would be a much more secure way to hold that pin in place.
I will bet that GM used those funky clips to save pennies in materials and labor to install them. They install just fine unless they become distorted from prior removal. They likely were not designed for re-use.
Carl
