For me, intent is the only thing that matters. If Nick Griffin were to always keep up to date with the latest politically correct lingo, that wouldn't make him not a racist, and if, for example, someone who was married to a black person with black kids used some outdated term to describe dark skin tone that wouldn't magically make them a racist either!
Personally I think it's really rare to need to mention it though, if I need to point someone out, for example at work, I would say "the man in the red jumper" or whatever, not "the black guy". My racist father always irrelevantly drops into conversation someone's skin tone or nationality if they're not white British, and it makes it obvious that he's trying to imply something.