I did a search trying to find out what size the bolts are that mount the rack to the roof. I have a 95 Tahoe and the PO removed the roof rack and I'm going to mount a light bar to the old front mounting holes if I can find out what size they are. so thanks for the help.

 

It may be best to go to local hardware store and take an approx measurement and get a few bolts to try. You may be able to order them direct from your GM dealer, but they will be expensive.

I looked on gmpartsdirect.com and they do not list the bolt separately. They only listed the assembly.

This site lists the bolts. It appears that there are a couple different sizes.
BOLT. Luggage Roof. LUGGAGE CARRIER; LUGGAGE CARRIER ( ); LUGGAGE CARRIER ( ). 1996 Chevrolet Tahoe 4WD # 12387478

Good luck with the light bar.

 

mulmur1's Approach would probably be mine as well, size up the hole and threads and pick up a few bolts... I'd be my guess that its something like a M6 or M8 though being a 95 it could be SAE and not metric... probably about 24 to 28 threads per inch...?