Definitely black looking natives were re-classified as 'Negro' back in the day. I had an uncle (now deceased) who was from Tulsa, his parents survived the massacre. He's a quarter Cherokee on his Mom's side. The Cherokee peoples could pass.
What most people don't know, the media doesn't talk about and the swirlers keep quiet about is that the Loving vs Virginia case that ended interracial marriage as illegal nationally, the woman was a native American re-classified as black.
The movie portrayed Mildred as black and Richard as white. “I know during those times there were only two colors, white and black, but she was Native-American. Both her parents were Native-American,” Loving said. The puzzle of Mildred Loving's heritage is deeply rooted in Virginia's complex racial history.
Anyway, that said, and although "only" an estimated 500,000 of the 20 million came to America as slaves, we were bred like cattle once here. There were an estimated 2 million ex slaves at the end of the civil war. I'm surprised it was that low. Why? Slaves were forced to breed. Not only that, the British ended the trans-Atlantic slave trade arbitrarily around 1809 or so. They actually had ships off the coast at the slave ports and other areas.
Anyway, because of this a whole new industry started in America: breeding farms. Especially in Maryland and Virginia. This replaced the transatlantic blockade. And it produced more slaves than if they came to Africa. Far more, safer, economical and strategic to breed blacks on a farm or plantation, than having to bring them in weeks on a ship, where some could die, etc.
I also see this "I'm Cherokee' thing by some, not all, but some folks as not trying to be seen as the rest of us. Basically trying to separate culturally so they can 'escape' racism and be treated differently (better or special) by whites.