I walked into an NK submarine from 20 years ago. I was not impressed. It had a regular old VCR sitting on a regular shelf like in a motorhome. And construction that would make a Victorian pipefitter blush. It ran aground during routine operations which is not so surprising given the utter lack of precision instruments evident. I would be surprised if in the past 20 years they went from that to a usable nuclear missile platform.

You can see photos from someone else here: http://www.catracing.org/hendrb/out-and-about-in-korea-tongi...

Your link explicitly mentions that the equipment found in this specific vessel is probably not the original one:

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.

The artwork is fantastic