Howard Koch

I haven't finished watching the movie yet, but I was stopped cold by a name in the hotel register about 9:30 into the film. Above George Taylor was Howard Koch, which was a very familiar name. Sure enough, although he wasn't part of the "Hollywood Ten," Koch, a screenwriter (War of the Worlds, contributed to Casablanca, et al) was in fact blacklisted (among the "Hollywood Nineteen," some of whom were "graylisted"), and was undoubtedly friends with director and writer Joseph L. Mankiewicz. This is one of those fun "hidden" items that savvy directors and writers placed in films. This movie was made before the blacklist, and I'm curious about whether Mankiewicz was just paying homage to his friend.

Anyone have any facts about this?