When Flagg and Quirt crawl through the lines in search of prisoners, Flagg picks up a German helmet and places it on his head. In the next sequence he is bare headed but he wears it in the farm house.
Dan Dailey calls Jack Pennick by his real name.
Captain Flagg's command was referred to as L Company, 5th Marines. In WWI Marine Companies were numbered. Prior to WWI they served independently with battalions and above were ad hoc organizations. 5th Marines should 5th Regiment. The change from Regiment to Marines wouldn't come until the 30s.