good post. I have heard in certain cases it is up to individual commisions, and other cases where it can be worked out in the contract. Can't remember, but I seem to remember a while back somebody had to shave before entering the ring. Again, I think it comes down to what commision the fight is under.
I remember during the Howard Eastman vs William Joppy fight Lederman or somebody had commented on Eastman's beard, saying that the rules stated it couldn't be longer than 1/4 of an inch. Berto being an Al Haymon fighter, the commission wasn't going to trim Berto's beard before the fight. I am not sure if the facial hair length rule is universal or whether it depends on the commission.