That is possible too.
But not every time one throws a punch do his knuckles get bruised.
Not sure any one looked at TM's knuckles...why would they?
If they throw a punch hard enough to knock a man off his feet then there should have been damage to Trayvons knuckles, IMO and the Funeral Director would have had to decide how to position Trayvons body in the casket, to fold his hands and if they could be shown or must be covered, he was in a perfect position to see if there appeared to be any fight damage on his hands.