if you're going to be rhinolining, I'd suggest welding the bed bolts to the box with a couple tack welds to help them hold them when removing the nuts or you'll risk turning the bolts in the holes in the bed. Since you're lining it, it shouldn't matter that the paint is scratched up.

My truck came apart fine once we welded the bolts in, heated them up real good, and doused them with PB blaster.