Im going to do some rust protection to the chassis and underbody of my 91 z28 with POR15. The back bumber support has got some pretty bad rust and to really do it right I need to get it off. There are 4 bolts on each side where it bolts to the chassis. Also there are some kind of grommet fasteners that attach the plastic bumber along the bottom in several places. These have a washer and some kind of clip in the back but are not hex bolts nor slotted screw type fasteners. Do you just pull these things straight out or what. Also if I take out the 8 bolts and the several fasteners to the bumper, will it fall right out?

Thanks. This is the worst rust on the car so I really want to get it out and do it right.