PT, that would be an illegal buck to kill, unless your a JR, disabled, or active military and anyone else that doesnt have to meet the antler restrictions. that would be the same as killing a 2x2 that you mistook for a 3x2 in a 3pt to a side area...

you have to gut and tag the deer with your buck tag, take it to a wildlife conservation officer and surrender the whole deer and pay a 25$ fine for a mistake kill. if after the investigation they conclude that it was an honest mistake that is reasonable, you pay the 25$ fine and i believe they give you a new buck tag...if they conclude that there should have not been a mistake, your looking at more fines and probably loosing your license for a few years.....