Got any pics? I buy my butts in the 2-packs at Sam's Club, and they come pretty-well trimmed. I just trimmed off a little of the "dangling" fat that they missed, and a few spots of the connective tissue (which does not get tender). I cooked with the fat-side up, due to the "self-basting" theory, and it turned out fantastic!
What rub/sauce did you use?