My take, FWIW, is that this Pancho was not Villa, but a modern fictional archetype. Additionally, it seems to me that Lefty is the subject of the first verse; a white boy gone on the road from the Midwest, ending up at loose ends south of the border. The subtext is that Lefty turned Pancho in to the Federales, resulting in Pancho's death, in exchange for which Lefty got the bread to leave Mexico and go back to Cincinatti. Probably looking for Spaw.

A