The laws governing self defense will be different in most states and countries. "Self defense" is not a crime, it is a plea. The distinction with training only comes into play if you are determined to have been an antagonist and are found guilty of a crime, in which case whether your hands would be considered deadly weapons depends on whether or not the judge/jury felt you had the reasonable capacity or intent to hurt or kill a person with your bare hands.
As far as registering ones hands as a deadly weapon is nothing more than an urban myth. One would have to register other parts of their anatomy as well. For instance an elbow to the temple could kill. Everyone is capable of killing another person with their bare hands, so if registering hands was the case then everyone should have to register them reguardless of training.
I searched the web and the only thing I was able to come up with was this: http://www.tafkac.org/faq2k/legal_2007.html