Jimmy Valentine and Boston Blackie

In Boston Blackie Goes Hollywood, Blackie has to open a safe in the apartment of his friend, Arthur Manleder. As he prepares to do it, the Runt says, "You haven't done it in a long time, Jimmy Valentine." That is a reference to a safecracker who was the main character in the 1928 film, Alias Jimmy Valentine, which starred William Haynes in the title role.