Allen Damron's performance of GRINGO PISTOLERO can be found on 2 compilation albums:

"Kerrville Folk Festival: The Silverwolf Years," Silverwolf CD 1030, 2002

"Texas Songwriters," SWC CD 1025, 2000.

I don't know whether there is any truth to the story, but apparently Francisco "Chico" Cano was a real person.

He is mentioned several times in:

The Texas Rangers and the Mexican Revolution: The Bloodiest Decade, 1910 – 1920 by Charles H. Harris, III, and Louis R. Sadler (Albuquerque: Univ. of New Mexico Press, 2007)

See also:

Bandido: The True Story of Chico Cano, the Last Western Bandit by Tony Cano and Janet Sochat (Canutillo, Tex.: Reata Press, 1997)

And:

Glenn's Texas History Blog

You can hear a fittingly macho performance by Andy Stanford at YouTube.