Corrected entry: Look at the dress uniforms they wear after the battle scene. They are Marines in their dress green uniform but it looks like the Army dress greens. Marines wear their rank and stripes on the sleeves in red.
Corrected entry: The premise of the movie was that a critical mass of Arabs were shooting at the embassy, which justified Jackson's decision to fire indiscriminately on the crowd. However, afterwards the camera scans over the bodies and not one weapon can be seen. Pause it and look for yourself. Did everyone manage to fall on top of their weapons as a last act before death?
Correction: At different points of the film the viewer is shown different "versions" of the embassy incident, some showing weapons and some not, adding to the effect of uncertainty as to what really happened during the shooting. However, the truth is revealed when the National Security Advisor is seen in his office viewing the tape from the security camera, which shows shooters firing at the embassy from within the crowd.
Corrected entry: There are over 300 bulletholes in the embassy building. Wouldn't it be possible to determine by simple technical research (angle of bulletholes) whether bullets were fired from the crowd below?
Correction: At the intial debriefing of the character played by Bruce Greenwood, the man debriefing him explains that FBI investigation shows that all the bullet holes in the embassy wall came from directly across the way from the snipers.
Correction: In the scene they are wearing service uniform A, which is green coat and trousers, not a dress uniform as the Marine dress uniform is the dress blue uniform. Only enlisted Marines wear rank ensign or red stripes on the sleeves of their green coat. There were several senior enlisted Marines shown in the scene with their stripes displayed appropriately on their sleeves. The officers in the scene were wearing their metal ensign on the shoulder of their coat and shirt collar as appropriate.