Lt. Goldman holds a 1911 pistol on the N. Vietnamese man then de-cocks the weapon. The 1911 has a manual safety that can be engaged and it is not recommended to be carried with the hammer down on a round in the chamber.
While dressed in his Class A uniform, SFC Anderson has only 2 combat hash marks on his right sleeve despite there having been numerous references to the fact that he is at the end of his third tour. A combat hash mark represents 6 months of combat duty, therefore he should have at least 6 hash marks.
The guys are sent out "sterile" to hide their ties to the US military, but following the scorpion scene, dog tags are visible.