I noticed the bottom of my rear bumper cover was hanging down and when I looked under neath all the bolts are gone. Why??? I did notice some rust there. So what should I do? Can I just get new bolts or what?????? If so what size will I need??

 

It should have plastic blind rivets. I got a box of them from the paint supply I always go to. P/n is 2036T... I don't know if that's universal or not.
Most local chain stores will carry these and even Lowe's in the specialty fastener section. There are only 2 size rivets GM uses, the small ones that hold the splach shield in the front fender and the large one's that hold the rear bumper cover on. You can take out a tail lamp and find more.
They look like so...

 

First thanks for the reply. Next, I dont have a lowes around here anywhere else I could get the part? I have Home Depot would they have it?

 

Apparently I forgot to add 'auto parts' to what I said. As in, auto part chain stores. They generallly have a small 'body fastener' section (usually located by the mics. bolts, washers, etc).

Using the power of Google, I also found the site I swiped that pic from a good while back... http://autobodysupplies.safeshopper.com/3/cat3.htm?712

 

Thanks man and I will be ordering some.

 

If your inner rear bumper is rusted so bad that those plastic rivets pulled out it's probably a good idea to replace it. I'm not sure how much a junkyard would charge for one but i can't imagine it being too much. It's pretty easy to replace, remove the tailights, remove the bumper, remove 8 bolts holding it on, put the new one on and put everything back together.