At 26 minutes, the terrorist on the roof aims at the ambassador's head. The audience sees the terrorist's point of view through the cross hairs of a scope. But,when the terrorist helps the young boy up on to the roof,minutes later, his rifle has no scope.
In the opening minutes when Peter Weller's character enters the US Embassy he presents his and his son's passports to the Marine Guard. This guard's uniform has a green/black name tag over his right breast pocket. Marines don't wear name tags on dress uniforms.