I don't think it would work well. The Vietnam war is associated with certain music through movies like Apocalypse Now and Full Metal Jacket. Having that music ingame adds to the Vietnam War (Movie) feel.
But in a modern setting it would just be annoying, like the kid on the bus playing his iPod so loud that the "music" comes out of his ass. It is next to impossible to select current music that isn't hated by a large part of the players.