If she's not wearing her kai-2 outfit (or any other official costume) nor her rigging, what is the basis of tagging Musashi Kai Ni?
Hair length is probably the easiest way to recognize Musashi/Musashi Kai from Musashi Kai Ni. Based on the official art, pre-K2 Musashi's hair is about waist length, while K2 Musashi's hair reaches somewhere between mid-thigh and knee.