JC: By the way, you never told me why you had to quit from Carl Perkins. WS: Carl told me two words that I just couldn't stand, and I had to leave. JC: What were those two words? WS: You're fired.
I'm not a war vet, much less a Vietnam vet, but I suspect Johnny gets as close in the American Recordings version of the song as any non-combat vet can get. (There are alternate versions of this song; the lyrics are inferior and should be skipped.)