Yeah, I have that problem too. They are big square plastic nuts, the problem is that the hole is an even bigger square. It appears that to keep it in, they doped it up with fingertip caulk! Not just on our LS, but on 2 others I ripped the the trunk liner out of to see what was really going on. In fact, a pair of the nuts are sitting on my desk right now, waiting for me to model up a replacement to 3D print out. I used, I think a 6mm, stainless hex head screw. But don't over tighten or you'll pull the nut right out!