Interesting thought exercise. My opinion is I don't expect to see any firearms from North Korea in my lifetime, which hopefully will not terminate until mid-century or later
Granted, Kim Jong-un is a morbidly obese smoker, but he is only 34-36, so I don't see his death and/or Korean re-unification any time soon. He's certainly not going to give up power willingly
Until North Korea ceases to exist as a separate political state with its current form of government or a close facsimile thereof, there isn’t a chance we'll see any imports of firearms from north of the 38th Parallel.
If the current government were to fall and out of the resulting chaos, a free democratic state emerged that was still separate from S. Korea , then perhaps we'll see some imports, but probably not firearms, as they simply wouldn't be a high priority. Trying to help them to convert to a market based economy would take enormous international market assistance. Production and trade of agricultural, food, energy, raw materials and durable consumer goods would be way higher on the priority list for developing a healthy economy.
We can look at other totalitarian regimes that have been toppled as historical examples of likely outcomes in regard to firearms imports. We haven’t seen any imports from Iraq or Afghanistan (not counting service member bringback antiques). We know there are plenty of firearms over there, but not even bolt action rifles or pistols have been imported, as far as I know. An aggravating factor may be that we have very few importers of any size left, and no, or very few, connections in the area. CIA and PW Arms are the only two large importers that come to mind in the milsurp area, with a smattering of other small players. Other factors are politics and priorities with regard to economic development and trade issues.
Another example from just across the 38th Parallel of a long time US ally, South Korea. Century hasn’t been able to get the previously negotiated deal for the South Korean M1 Garands and Carbines approved under past or current administrations, so if a North Korean state were to become unified with South Korea in the future there'd be the same hurdles to those imports, and reunification is probably the best case scenario in regard to imports of firearms.