I would probably pass that buck, the only way/reason that I would shoot that buck is if that drop tine seemed to cause pain or extreme discomfort to the deer. Which could very easily happen if another point where to grow underneath the deers jaw. Most of the time when a deer is injuried and his antlers become nontyicalish, once he recovers from his injury his antlers will grow back like normal. If a deer suffers an injury that will not allow the deer to heal normally then the antlers will stay nontyicalish. But this deer might very well be a normal looking 8 or 10 pointer next year. If his leg heals up then you probably wont regonize him next season.