Maybe these?
https://sdparts.com/i-19870002-chevr...ms-qty-16.html
Not sure that's the best price, but from the description it comes from GM and is self-aligning.
EDIT: I see the issue now. For 16 of them it's $92. But for just one, it's about $26. Strange marketing. Find a buddy who needs a few and split the box. Summit has them, too. You'd think they'd be smart enough to split up a box of 16.