edit: what he said /\/\/\
the center trim peice is attached to that huge plastic thing behind your plate when you take it off the car youll see the clips running all along the top and buttom, and youll have to take the kinda heat shield lookin thing off also that protects your hatch lock. The plate lights also have to come out for it to come out the trim also has clips behind it that hold the plastic peice to the metal too.
the trim is like permantly connected to that plastic peice that goes behind your plate.
that is of course if its the same as a pre 89
edit twice: and IIRC there isnt a gasket for the center section.
edit once more: also dont worry if you break a few clips its all screwed in by the plate lights.