Factual error: Alec Baldwin opens a pack of Chesterfield cigarettes and they have a filter. This is in the late 50's - Chesterfields did not have filters until 1966.
Factual error: Through the last third of the movie Edward Norton has a cut above his left eye. It is closed with an adhesive strip. It wasn't until 1962 that 3M™ Steri-Strip™ Skin Closures were introduced to the health care world. A stitch or two would have been less distracting, and would have been better suited to the gritty feel that the movie was trying to achieve.