I have seen them both ways, the one from my ‘71 GT was pretty much just natural. The original one from my ‘74 was definitely painted black, but, I couldn’t tell you if that was original.
I couldn’t tell you what the one on my Challenger is, it’s under so much grime I can’t tell. But as a Utah car that then went to Florida, I can tell you it is one of the few parts of the car that doesn’t have some measure of rust.