Our company manufactures parts at our various shop locations around the world to our internal standards and procedures that uses the AWS code for weld quality and other welding requirements.  Sometimes when we manufacture an assembly that will be used in another country, the customer from that country may elect to specify compliance with other specifications.  For example, sometimes in our Australia shop, the Australian customers want documentation that supports the parts were manufactured in accordance to the Aussi welding quality standards, to include Austalian welder qualification.  (Some of the Aussi welding standards are Very similar to the AWS code).  We have to comply to sell the euqipment there.

I guess it also depends on what you are manufacturing.  If for example, you manufacture structural steel for buildings to be errected in Mexico...you probably should be familiar with, and in compliance with the Mexican building codes.  If you are welding structural steel in Mexico, to be imported into the US, then you should be in compliance with the applicable AWS codes that you are required to be complied with as if the product was manufactured here.  If you are manufacturing mechanical weldments for your large conveyor system for example, I would coninue to follow your current manufacturing processes ( that like you said, currently include AWS procedures and AWS welding qualification), unless a customer requests different.

Sorry...No hablo regarding the request for translated spanish code books.  Maybe someone else can provide some info.

Lincoln used to publish good welding books in Spanish that were distributed for free. One of them was: "Guia para sobrestantes de taller de soldadura", which means: "The welding shop foremen's hanbook".
I don't know if they (the books) are still available. Try and good luck.
Giovanni S. Crisi
Sao Paulo - Brazil