You always go to " GM parts giant.com " . Enter your VIN it will take to parts category for your year model . Then choose what section, steering , drivetrain , body, exhaust. Then scroll through the listed parts,. Tip: it will give you the GM part number, and AC Delco number if carried by them. Also if a type of hardware the description will size it; 1/4 x 20, 4 inch stud, or 6mm x 12, 100mm bolt. Drain plug 1/2 npt with gasket.
GM and ACDelco part numbers can be sourced from multiple vendors, not just GM.
The parts may be available from GM, but the number can still be good on the after parts market.
A Lot of GM hardware, that I'm not sure about I'll use the Full parts sites, listing all parts including the no longer available parts; not the abbreviated websites that don't list all parts.
Why guess or wait for responses that may never show, or close but quite correct.
Good luck!