Nothing in the article makes it clear (to me, at least) that it isn’t the North Koreans. They have the motive and opportunity, you are questioning the means. It is interesting that a lot of the bogus currency has been traced to North Korean diplomats. Like I said, how else does he finance all those Mercedes and Hennessey?
Let me ask you this. What better way to find out who or what is funding North Korea than to distribute bank notes and watch where they go to? North Korea doesn't have the means to generate hard currency, yet they come up with it. If you make 10 different versions of the $100 bill, each perfect except for one single, minute, deliberate flaw, then distribute these notes through 10 different channels, wouldn't the version(s) the North Koreans are caught with identify who was funding them?