Factual error: During the "Vietnam Scene" at the beginning you see a very long take of an AK47 muzzle appearing slowly from a bush.The problem is, it has the slopping muzzle brake of the AKM, not the plain muzzle of an AK47. The AKM was not in service in 1968, and was never supplied to North Vietnam anyway.
Factual error: When Samuel L. Jackson stopped to salute the lowering of the flag, the first song of the Retreat Ceremony (Retreat) was playing. On real military bases, the flag stays in place during the first song while all military members are required to stand at Attention (unless they are in formation; which the person in charge will give the command of Parade Rest) and at the playing of the second song (To The Colors) the flag is lowered and they are required to salute.
Factual error: In the US Embassy scene in the Ambassador's office, President Clinton and Vice President Gore's pictures are framed on the wall. In an US Embassy the President and the Secretary of State's picture are hung on the wall, not the Vice President. In this case the Secretary of State's picture should have been either Warren Christopher or Madeleine Albright who were the Secretary of States under Clinton.