I never liked camo painted anything to be honest. Never saw the need for it. I sold the only camo rifle I had. But hunted with blued and stainless and never once saw a critter bolt from either of them. I always thought it a gimmick to sell something at a more expensive price.
it is a shame about the man's rifle though. I think I would just wipe it all off and if he didn't like it, paint it flat black and learn a lesson. Or he could maybe blue the thing.