You mean the earliest official to do this? I thought it might have been George Siler, but he never refereed a light heavyweight title contest. (The flyweight class was created several years after his death.) I'd need to take a closer look at the record to determine the first to do this in all divisions that existed at the time of this achievement.
Thanks! Actually I just got home from the movies and now I am getting ready to go to the New Jersey Boxing Hall of Fame meeting, where I am the President.