i got my blackouts for my bird today but am having problems. what a surprise

anyways the kit comes in 3 pieces. the two for the taillights and the center piece. the side pieces line up fine with the lights. they rest flush against them. however the center piece doesn't rest flush and lookin at it from the side, it has more of a "curve" than the side pieces with doesn't make it line up correctly. anyone with these blackouts have this problem? the package says for Firebirds except T/A's up to 92. however i'm thinkin the centerpiece isn't the right one.