That lip can be found online for $100, and they're held in by a few rivets if my memory is good. You do not need a dealer to remove and install a new one. I yanked mine off and tossed it in the trash.
Edit: apparently I'm showing early signs of senile. It's held on by some screws. I do remember mine wasn't on very tight because I was able to yank it off in a parking lot.
http://www.370zcoupe.com/ACCS/1TK16.PDF