^^ Thanks for letting us know. I was going to remove the whole rear bumper to remove the covers.

As for the fronts, what's holding in the screws for the licence plates? Is there a metal retainer in the back holding them in?

 

My plate was just held on by two self tapping screw into the plastic bumper, no clips and holes seem to be a dealer option, aka where ever he was holding the plate when he started to run the screws in.