I actually told about a C-46 that shot down a Japanese fighter during the hump operation. Never did find out the fighter type though. From my presentation about the hump:
While attacks by Japanese fighters were occasional, they did happen. In one incident, Captain Wally Gayda opened a forward cabin window and aimed a Browning automatic rifle through it. He managed to shoot down one of his attackers. As far as is known, this is the only instance of an enemy aircraft kill by a C-46 Commando!