The pass-code used by Bruce to lock Damian's Sai is 1939. 1939 is the year that Batman made his debut in Detective Comics #27.
Mixed with New 52s "Court of Owls" storyline, and Detective Comics #1, where the doll maker made his first and only appearance so far in the new 52 reboot.
One of the few non-comedy roles "Weird Al" Yankovic has performed.
The monastery Batman refers to at the end of the movie is in Nanda parbat. Where he received some of his training.