How does your bumper fit? As you know the bumper is separately mounted and can be shimmed to it's brackets. Also to Charles point if the guards and/or brackets are repo they may need massaging!
I have a Nordan back bumper, the brackets and guards are original. The guards have a gap to the bumper curve that's pretty consistant 1/8"-3/16".
My '64 1/2 vert. Ordered May '64. D code 4 speed, handling package, caspian blue, accent group, Ford blue manual top.
'68 vert. driver. Owned since Apr '78. C code AT, AC, PS, P disc B, PT lime gold, standard black interior and top. NOS RF fender and left quarter.New top and folding glass.