That in mob of the dead in the cafeteria area, there is a sign above the kitchen dated January 1 1932, which makes me think the map is set on December 31st, 1931.

Also the B's are missing from Bread and Butter, I'm not sure if there is any significance, ill be spending the next hour or two exploring the map looking for other things people haven't yet found.

I know people most likely know about this, just letting those that don't know.

There is also a sign in the laundry room saying 'You are required to work at whatever you are told to do. Use perks to increase performance.'

To me this says that this is either a little easter egg the developers threw in referring to the player, or the prison had perks before the actual outbreak.

Leave suggestions below please, ill leave anything else I find below.