I have no idea if they did it in NK at any point. I am pretty sure it is nothing you can see in current North Korea. It is a bit older already but in 2008 two Austrians were travelling by rail, via Russia to North Korea. They entered the country via north by train in a way, that the North Korean regime officially allowed at that time but apparently had no process for to handle in any way, because they probably did not expect anyone crazy enough to take the full Transsib to North Korea. What they managed was travelling by train in North Korea, all the way from the very north, to the capital Pyongyang, where they were then greeted by their "guides" as usual for Western tourists.

They took a lot of pictures and videos of rural North Korea and its people and they had uncensored contact with regular North Koreans on the train, who were understandably very intrigued by those very strange people from abroad. I think to this day, the material they took is among the best, uncensored and non-biased evidence of life in North Korea. Limited as it may be from simply travelling by train across the country.

https://youtu.be/b1mzXFAzUjQ?t=694