Yes, I would -- just wash off the dark and leave everything else. Use a 3% w/v brine solution (3 grams of salt in 100 ml of water). It's hard to tell from the picture. It may be mildew (which would mean that your humidity was just a touch too high) or it may be mucor. Mucor would be a bit unlucky as it is likely to spread and give your cheeses a mottled look. Won't really affect anything else, though. If that's the case, you can feel good that your cheeses are authentic as they would have been before 1970 when the industry decided that only white would do ;-). If it is mildew, then it will probably stain the rind, but for a bloomy rind you won't see it anyway. Just in case, I would isolate that one cheese in another box if you can. But they are looking really good so far!