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.