Before he gets shot, Gallegher tells Manny he's "just a kid", but Dick York was 29 years old when he played the role of Manny, too old to be considered a kid.
Mr. Williams says that Christmas is the day after tomorrow, so it is December 23rd when he gives Manny a job to complete. In a later scene, he says it has been a week since their last discussion, therefore, it must be December 30th. In this scene, Mr. Williams says that New Years Eve is a few days away when it is actually the next day.