The paratroopers of U.S. Army's famous 101st Airborne Division, known as "The Screaming Eagles" due to their distinctive shoulder patch (a gold-beaked, red-tongued white-headed bald eagle on a black shield), were feared and respected by their North Vietnamese and Viet Cong enemies in Vietnam. The Vietnamese Communists called 101st troops "Chicken Men" because of the eagle shoulder patches, and had a cautious saying about them - "beware of the Chicken Men."
The closing credits include a famous poem about the war written by Major Michael Davis O'Donnell on January 1, 1970. O'Donnell was declared missing in action on March 24, 1970 after piloting a helicopter on an extraction mission inside Cambodia. He was declared killed in action in 1978. His remains were recovered and identified with DNA testing many years later, and were interred at Arlington National Cemetery in 2001.
Near the end of the film, there is a scene where a soldier, his face covered with bandages, is blindly reaching out to his comrades as they hurry past him. This is taken from a famous picture taken at the real Hamburger Hill.
After the May 17 battle, Dylan McDermott, as Sgt. Frantz, vehemently tells an Army photographer who shows up to "Unass my AO!" In the condensed language of GI slang, it is an order to move his ass out of the sergeant's Area of Operations, and in this context it expresses the infantry GI's contempt for soldiers who don't fight.
This movie's opening prologue states: "On 10 May 1969 Troops of the 101st Airborne Division engaged the enemy at the base of Hill 937 in the A Shau Valley. Ten days and eleven bloody assaults later, the Troops who fought there called it . . . HAMBURGER HILL."