Factual error: The final scene of the movie has Col. Kirby and the little Vietnamese boy supposedly on the beach at Da Nang, Vietnam. Kirby is saying, "The future of 'nam is you, kid", and the camera pans out to the sea and the sun is going down. The sun's sinking in the east...
Suggested correction: Nowhere in the film are we told where in Vietnam the Green Beret base is, just that it is in South Vietnam (of course). South Vietnam has a Western coast, along the Gulf of Thailand, along which anyone can watch the sun set over the sea.
Around the 18:00 - 18:30 mark a character welcomes John Wayne to Da Nang. This base is returned to throughout the film, including the infamous sun setting in the east scene. Da Nang's beaches face to the Northeast. Only when you get south of Nha Trang does the Vietnamese coast begin to offer a south to southwest horizon on the ocean.
Factual error: When Petersen is first confronted by Col. Kirby for pilfering from his unit, Petersen neither comes to attention nor salutes Col Kirby (he should have done this as soon as he saw the Col.) This is such a huge breach of military courtesy, that one of the senior NCOs , if not Col. Kirby himself, would have called him on it instantly.
Factual error: When the Navy Lt. shows up at Camp Aavoy 29, he states that he is part of the 91st Sea Bees. However when you see him driving his bulldozer, it is marked U.S. ARMY. The Sea Bees are part of the Navy and have their own equipment.
Factual error: After returning to camp Savoy 29, Cpt. Nimh states that he wants to go home to Hanoi but first he wants to "kill all filthy stinking cong." The civil war in Vietnam was between the Republic of South Vietnam and the Viet Cong. North Vietnam (the capitol of which is Hanoi) was a separate country that aided the Viet Cong. So even if Cpt. Nimh killed every single "filthy stinking Cong" in South Vietnam, North Vietnam would still be communist, and he still couldn't go home.
Suggested correction: The Viet - Cong were pretty much wiped out during the TET offensive of 1968, North Vietnam won because they out - lasted the U. S and of course were supplied by PEKING and RUSSIA. Afghanistan was lost for very much the same reason, the opposition being supplied by their allies next door, and even though American service deaths had gone down to almost nothing, the U.S. bungled its departure, giving over much material.