Take a look here:
Look at that first photo.
Don't those books look eerily like WT literature?
The ones in the top 2 rows look exactly like the last of the hard-bound "thin" yearbooks. Off to the right is the spitting image of a Reasoning book.
Below that you've got the modern cheap paperback look - down to a T. The cover photographs, the font - shoot, they even look like they are 192 pages long!
And for even more freakiness, check out the photos just below - it is virtually exactly the same as the WTS "paradise" pictures, except (of course) everyone appears to be Korean.
I have no idea what this all means - probably nothing more than a coincidence.
On the other hand, what better teacher for the North Koreans on how to effectively run an autocratic no-dissent-allowed dictatorship than the WTS?