During the Patrol, SGT. Johnny Martin is carrying an M1 rifle while in the German outpost, but switches to a Thompson Submachine Gun while they patrol is trying to get back across the river; then switches back to the M1 again while they are getting brief for the 2nd patrol.
When Lieutenant Jones meets Sergeant Malarky for the first time, Sergeant Malarky is seen wearing his battle jacket with the sleeve insignia of a US Army Staff Sergeant (three stripes with one "rocker" underneath). In a later scene, that same day, after Sergeant Malarky has showered and is wearing a newer, cleaner battle jacket, he is seen wearing the sleeve insignia of a US Army Sergeant First Class (three stripes with two rockers underneath).
In his voiceover narration, David Webster mentions that he had been with Easy Company since its formation, but this is not true. While he had been with the REGIMENT since its formation, he originally trained, and jumped into Normandy on D-Day, with Headquarters Company. It was not until after D-Day that he transferred, upon his own request, to Easy, with whom he would remain until the end of the war.