As I recall, Mexico was never a hot bed of gun manufacturing.
Regarding that, there is no surprise. Europe, britain and the US started out the quality arms trade. Japan wasn't making and selling guns for trade back when these advanced manufacturing companies were sending 1894s and mausers all over the world, including mexico. Between mexico, china, and japan, for example, there weren't any strong industrial bases. Even today Mexico isn't a tech or manufacturing giant, where the asian countries make everything that we buy and do it with quality workmanship.
Things haven't really changed too much as far as exports. As long as there have been import/export systems, there have been regional specialties that supplied most needs.
Right now, the top import item to the us from mexico is cars at 90 billion according to the us trade representative. They make mechanical parts, machines, and tools. Our agriculture and food imports are about 26 billion. They were far behind on the skilled labor development and technology development, and lost the chance. Now it seems that they are taking up a lot of the Rust belt industries. Appliances, machinery, power tools, etc. Brazil, however, did create a south american gun industry creating copies of various guns throughout history.
We get everything from china, tech from korea and japan, clothing from southeast asia and india, shoes from china, I even bought a japanese power tool 'made by' ryobi in china.
I can't go into any talk about asian markets as the 150 years that they have been part of our system have been really, really turbulent. Japan did, however, do a lot of machinery and tool exporting over hear for decades after the war, and now make great machinery. Cars started when, in the sixties? The japanese could create a magnificent arms industry if they chose to.
https://ustr.gov/countries-regions/americas/mexico
The top import categories (2-digit HS) in 2018 were: vehicles ($93 billion), electrical machinery ($64 billion), machinery ($63 billion), mineral fuels ($16 billion), and optical and medical instruments ($15 billion).
U.S. total imports of agricultural products from Mexico totaled $26 billion in 2018, our largest supplier of agricultural imports. Leading categories include: fresh vegetables ($5.9 billion), other fresh fruit ($5.8 billion), wine and beer ($3.6 billion), snack foods ($2.2 billion), and processed fruit & vegetables ($1.7 billion).
