That said, there were other hood stripes that did come in other colors. I'm thinking specifically the 340 Wedge decal which was white, the '70 Charger engine callouts (V24). Also the hood stripes on Sport Fury GTs which came in white and orange as well as black. These hood stripes weren't coded they matched the side strobe stripes which were coded. Note, that these were also all decals, not paint.
Some applications of V21 were painted, and others were decals, but they were always black.
So was the Sizzler-style hood stripe V21? If so, then it was black. If not, then it could be other colors I suppose, especially if it was a decal. I really don't know much about A-Bodies.