I would have to agree with this basically. I had my cam nitrided and really dont remember just how it looked but I do know most new flat tappet cams I look at seem to have a black surface on the lobes when new even if not nitrided. Myself I was told nitriding is a hardening of the cam and I really cant see that being a surface coating that could rub off. I bought my custom grind cam from Dwayne and he told me Comp did the nitriding on it. And I can tell you its been in my eng since I fired it up in June 2011 and is still going strong and has not wiped any lobes or had any problems at all. If I were you and I was worried about it I would send it back to Comp and let them look at it as even if they say its fine that will give you peace of mind. Comp is stepping up to the plate and doing what they can. And I agree with them that its tuff to tell by just pics whats going on. I feel its a surface coating like was said maybe for rust prevention because as I said I cant see a hardening process as nitriding rubbing off with your fingers. It will most likely be fine but why not send it back and let them make sure its right ? Everyone can and does make mistakes and if they did the right thing to do is step up to the plate and make sure its ok and correct it if it is not and Comp seems to be stepping up to the plate if they did make a mistake which is the best anyone can do. Ron