There are many answers to this question, certainly there are reproductions being sold as in just about all areas of collecting. I also know of an ex-collector of Imperial Japanese items (Warren Sessler), who was instrumental in bringing in many great Japanese items in the 70s. Mr Sessler is said to have moved to China, near the border of the DPRK and he deals in DPRK militaria and medals. So perhaps some are being brought out by him and others like him. The Chinese are active traders on many auction sites so it's not unreasonable to see them selling DPRK items.
As for trades and exports, the DPRK exports weapons to many countries like Burma ( I refuse to use the other name), Iran, and formerly Iraq to name a few. So there are a few ways that items come out. I am sure there are many more. Scott.