It's not a question to be tossed aside, but I don't think the evidence would bear it. For one thing, nothing made in DPRK is going to be sold through South Korea. They're at war still, not trading and communicating with each other.
Secondly, while DPRK has a lot of people in labor camps, they're starving and their education level is comparable to 4th grade. I don't think you can get exacting standards of quality out of starved forced laborers, but even if you could, you'd still be dealing with the complete lack of a supply chain in North Korea. There are plenty of countries in the area with established supply chains and populations experienced at making these kinds of things, but DPRK isn't one of them.
Third, there just isn't a lot coming out of DPRK in the first place. I've heard of paper flowers made in their labor camps being exported to China and Japan, but in general the trade situation is pretty much a trickle.
It's possible, and there are certainly people around better informed than me, but it doesn't sound like the best or most plausible explanation to me.