In an early scene in his office, Drake's pencil drawing of the dove is smooth in one shot, then suddenly appears crumpled in the very next shot.
The rifles used by the platoon to which Pvt. Adrian belongs are actually M1 Garands which had been cosmetically modified to attempt to make them look like the M14 rifles in use at that time.
As Adrian and Drake leave the bus station, a light is reflected in the door.