I had to take the rear license plate off and when I went to put it back on I noticed that there is a bolt behind the bumber that the nut goes into. Both of the bolts had moved slightly and when I tried to move thyem back they fell off. Now I can't get the plate on and the dealer told me to drill into the bumber Has anyone heard of a clip that can fit in there or do I have to take the bumper off??

 

You might be able to get by with drywall anchors or license plate attaching plugs like the ones in the photo. You can get them at any auto parts store.