I don’t know if this was the same documentary, but Michael Palin (Monty Python) did one of his travel documentaries, called Himalaya. The whole production was excellent, but his crew did pass through some small Pakistani village with a thriving hand-made gun industry.
Palin made the very clear point that these guns were pretty much exact functional replicas of nearly any gun otherwise available, all for a fraction of the cost. I remember him being quite startled by live-fire testing in a narrow alley.
Great show! Made we want to visit. Sort of.
I'm not sure either but I vaguely remember that this village was filled with arms dealers and known for its lawlessness so the film crew had to tread carefully up there.....