The US Embassy in Beirut was bombed in April 1983, six months before the Marine Barracks, not Army barracks, were bombed. 'Death Before Dishonor' uses these incidents in the same manner the Heartbreak Ridge (1986) used the invasion of Grenada.
The suicide car bombing in this film was probably one out of hundreds of typical incidents in such a troubled spot. Then the abduction of the Colonel (Brian Keith) had a composite incident with the factual abduction of U.S. Marine Lt. Colonel William Richard Higgins during a U.N. peacekeeping mission in 1988. The movie character was rescued, while Higgins was tortured and executed.
The US military in Lebanon aka "Jamal" the event with the suicide car bomber is based on a true event in Beirut 1983 but it was an American army barrack not an American embassy.
Cast members, Fred Dryer and Brian Keith, about eight years later both appeared in The Return of Hunter: Everyone Walks in L.A. (1995).
Brian Keith served in the United States Marine Corps in World War II, and received an Air Medal. He was the rear-facing gunner on an SBD Dauntless, a scout/dive bomber, used extensively by the Marine Corps and Navy, that saw a great deal of action in the Pacific during WWII. His weapons were twin-mounted .30 caliber Browning machine guns. He particularly saw action on Rabal in the Pacific.