1978 GMC Trucks Caballero Sales Folder. Caballero the new way to go. GMC's Caballero is NEW! It's one of a new generation of hard-working, youthful, good-looking vehicles. It's lighter than last year's models and trimmer on the outside, yet it's roomy inside and fuel-efficient. It's not one...but three: Caballero, Caballero Laredo, or Diablo. Goes into further detail about the different models. Back shows some of the accessories available for the Caballero as well as an Engine/Transmission Selector Guide. Very good condition. Form ADV 78-5