According to the dialogue card at 1:19:06, the big fight between Jack Saunders and Bob Corby was refereed by Eugene Corri, who entered the ring wearing a tux. Corri made boxing history in December 1907 by being the first referee to referee inside the ring during a fight.
According to modern sources, this movie contains the earliest example on film of the obscene hand gesture known as The Middle Finger. Other contemporary movies where a character uses the gesture are Harold Lloyd in Speedy (1928), Richard Dix in The Lost Squadron (1932), and Bette Davis to Douglas Fairbanks Jr. in Parachute Jumper (1933).
The final boxing match appears to be taking place in the Royal Albert Hall.
This movie was released in 1929 in France under the title "Le ring", as many magazines (such as Cinémagazine, Le film complet) prove. However, for some reason, at some point around the 1960s, it was confused with a Fred Niblo movie released at the same time in France, "Two Lovers (1928)," which French title was "Le masque de cuir", in reference to the Leatherface character in it. This title has been erroneously used for the Hitchcock movie in various books from the 1960s, and for a DVD release, although the plot has nothing whatsoever to do with a leather mask.