There is a scene stuck in my mind: Bad guys arrive to take over the good guys moonbase, and the good guys hide behind brightly painted rock outcroppings so they don't accidently get shot by their own side when the battle takes place. Basicly, the idea was to shoot everybody that wasn't hiding behind the piles of colored rocks, and to never shoot at those rocks where the defenders were placed. I don't believe much of the tale took place on the moon, just a chapter or two.

I read it at least 20 or 30 years ago and can't reconcile this scene with the rest of the book, or I'd be able to give you more details. I do think it was a 1970's apocalyptic earth story. Does anybody know which one?