Just make sure your reproduction emblem (if thats what your using) matches the template. Pins on repro emblems have been know to be off from the originals.
Theres a drawing in a post around here showing the amount the emblem moved, think its 3.44". All pin holes moved forward the exact same amount. Make a template of your existing holes and slide it forward that much.http://www.camaros.org/forum/index.php?topic=8171.0
Same deal with the spoiler, repro ones have the studs sticking out in various different angles from true 90 degrees from the bottom face of the spoiler. Stick the studs through a sheet of cardboard, trace the bottom outline of the spoiler on the cardboard, cut it out, find the center and align it so the little nbs on the back of the spoiler, not the smaller mounting base, are flush with the back edge of the trunk lid, mark and drill your holes. Drill the holes slightly larger than the 1/4" studs.