I tried to remove the rear license plate holder only to find the four screws holding the plate had rusted solid into the metal sleeves. Trying to remove screws resulted in stripping the inserts out of the plastic. Dealer replaced the holder on warranty. Suggestion: check the screws and if you can remove them - grease them. If you can't, get the holder replaced.
Also examine the paint behind each of the four screws for damage as an eager mechanic can damage the paint when installing the rear plate.