I have lived in the "southwest" for a lot of years and I rarely find "tocino" on any authentic Mexican restaurant menu. The closest thing I can think of is chicarones (fried pork skins.) They taste kind of smokey but are used mostly as a snack.
I know that they use lard in the form of pork fat in their tortillas, tamales, and for frying carnitas.
I am surprised that smoking did not become popular in the desert southwest as a way to preserve and dry meat for storage. Seems like a natural thing to do since refrigeration was so hard to come by.
It is known that native tribes in the Americas used to dry meat into jerky and that the northwestern tribes used smoking as a means to preserve fish and meats.
Pemican was a staple of many tribes in the central Americas. Consisting mostly of bison fat, some dried meat, some prairie grass, and maybe some berries or rosehips. A very nurishing meal for an active people.
Some say that the Spanish brought The style of "barbacoa" to the Americas. Some say that it was the Africans who brought it over from their culture as slaves in the south to make tough cuts of meat tolerable to eat.
Alas, bacon as we know it does not much exist in Mexican cuisene (as far as I know.)