Rob, those are the lights. The rubber is a blind that directs the light down toward the plate only, and not in the eyes of the following car. You can see the plastic lens behind the rubber guard.
Get into the trunk open the square hatches on the wall next to the lock, undo the small bolts from the outside, pull the harness back through the holes into the trunk, open the casing, and replace the big double ended (not sure what you call them?) bulbs. Should be fine.
Mike Mizesko
Columbus, OH