one kind of man who tells the truth -- a theory

"There's one kind of man who tells the truth, that's a dead man.
Or a Gringo like me."

That's a couplet from "A Gringo like me," from the movie Gunfight at Red Sands. I haven't seen the movie, but I love the song. I first heard it when I was at a Spaghetti Western festival at the Film Forum in Manhattan. The Film Forum was playing it between movies. So I heard it over and over and over again. I, for course loved it. Still do. It's a damn catchy tune. You can hear it below. Of course, the fact is that a dead man doesn't tell the truth. Dead men generally don't talk much at all.

So I have a theory. Gunfight was an Italian/Spanish coproduction. Is it possible that the line was supposed to be "There's one kind of man who doesn't lie, that's a dead man" but got mistranslated or something?

Or maybe whoever wrote it thought it was a catchy line.

Anyone out there know?