None of the ribbons on Waco's khaki shirt really exist.
Throughout the movie, the enlisted men and their officers salute each other, even though they're in a combat zone. This is not done in the real Army because it identifies officers as potential targets for snipers.
In the cast listing, Robert Wagner is listed as Sfc/Pvt. Sam Francis Gifford. He should be listed as T/Sgt/Pvt. Sam Francis Gifford. The rank Sfc (Sergeant First Class) did not exist during WWII. At that time it was T/Sgt (Technical Sergeant).
After Gifford and his men procure a couple of cases of beer, and upon drinking a can each, beer spays over the soldiers' faces and uniforms. In the next shot, their faces and uniforms are dry.
The soldiers in this movie are wearing jump-type boots. They should be wearing either combat boots or leggings. Jump-type boots were not issued until well after WW II.
Robert Wagner's character is supposed to be a Southerner, but he has no perceptible accent when he speaks.