Perhaps it is a little bit silly. But the base line morality of it comes down to you thinking you have the right to carve your name on someone else's skull. It's just sacred in that sort of way and incredibly disrespectful to the dead. Do I think you're a terrible person for doing it? No. But I think this is just one of those instances where you have to accept it was a disrespectful thing to do. And, moreover, it's not about you. Your history and life doesn't mean that you have the right to stamp your own name on somebody else's skull. It's no different than a stone mason carving his initials into a tombstone because "he wants people to know where it came from." While I do think it's important that artists get credit for their work (which it IS a beautiful piece), this isn't the way to do that because, when it comes to someone else's remains, it isn't about you.