Replacing plastic rear bumper brackets

New to the forum and hoping for guidance. The rear bumper on my 2005 Durango (5.7L Hemi) has broken plastic bumper brackets. Those are on order along with 4 new plastic push-in fasteners that attach to the metal brackets at the back of the vehicle.

My question is: as I dis-assemble and re-assemble the plastic brackets lefta nd right, does anyone know if I will need to remove the push-in fasteners at the rear underside of the bumper,or is it best to just leave those in place?