For those interested, here's an article on the NK ballistic missile sub: http://www.hisutton.com/North%20Koreas%20next%20Ballistic%20...
And ballistic missile subs of the world: http://www.hisutton.com/Nuclear%20Missile%20Submarines.html
And ballistic missile subs of the world: http://www.hisutton.com/Nuclear%20Missile%20Submarines.html
You can see photos from someone else here: http://www.catracing.org/hendrb/out-and-about-in-korea-tongi...
Speaking of equipment, it was obvious the submarine was stripped of any useful electronic equipment, such as navigation or communication equipment. In its place were items taken from a dump.
I imagine that all the original equipment was removed and analyzed by a South Korean Intelligence Service before the Sub became accessible to the public.