The original grill back bars would have been an off white, ("Windsor" White IIRC.) The black primer you speak of if a true e-coat is fine to leave on. Taking the grills apart is a pain just due to the number of bolts (I believe on a repop) or even more so on the original (rivets). I painted my original chrome grill back bars with white without disassembling. My wife is wonderful and VERY detailed oriented. She taped them off and did a fabulous job. It did take a while, but probably less than disassembly and re-assembly
