What part of the grille do I black out on a 68 B'cuda?

The chrome grill option was only available on the "spring special" 1968 Barracudas. They were part of a sale "package" that also included wire hubcaps, red reflective tape on decklid & sport stripes. Standard grills were grey with the black horizontal bars. Here are a couple pics of black grills & 1 with silver.