//What do I know. We've only got 2 sort of black guys in the town and I can't say I ever heard race mentioned.//
Maybe not, spicey. But if they were being referred to you can bet your boots that they would be mentioned as “You know, those two black guys.” There would be nothing wrong with that. No more than other would be if someone said “You know, that guy with only one leg.” It’s a description which narrows down the number of people it could be.
//Within a generation that would have mysteriously become the most awful insult ever, how dare you even consider using it.//
You’re joking, OG. Within about a fortnight. As soon as the professional offence takers have had time to digest it and put an interpretation on it that goes back over 200 years, ideally with a connection to the slave trade.