Undergrad decisions can almost always be appealed. As for Law School, I have no clue if it's even an option. As an above poster said, it's not like it can hurt you - but I wouldn't count on getting in somewhere that declined you. Unlike undergrad, who is really more willing to come and talk to you more about everything, most law schools have already probably considered anything they care about.
But give it a shot, it's not like it can hurt.