The Iron Bodyguard thing was a stupid mistake on my part

.
According to the Bey Logan commentary on the Celestial DVD of the Heroic Ones the title literally means "Thirteen sons of the King". I think it may be an archaic term, hence it doesn't show up in any of my dictionaries.
A few more:
Blood Brothers (1973) – Cantonese title: Chik3 Ma5 Translation: The Assassination of Ma
Five Venoms (1978) – Cantonese title: Ng5 Duk6 Translation: Five Venoms
Have Sword, Will Travel (1969) - Cantonese title: Bo2 Biu1 Translation: The Bodyguard
Once a thief (1991) – Cantonese title: Jung1 Waang4 Sei3 hoi2 Lit. Translation: Crossing in all directions
One quick question: are you sure the characters given in the DB for Chinese Boxer (1970) are correct?