Can someone tell me what these missing bolts are and where to obtain them, outside of a junkyard?

 

I can verify they are 10 mm bolts.

 

The fit most every late model gm fwd car and truck even to current date. They are not Fbody specific bone yards best place to source em. take a 10mm on a 1/4 inch ratchet and your GTG

Or go run by a local body shop and straight up ask if they have a spare bolts pile. mines huge