When did they have any?
You’d be surprised. Up until 1980.
See the overview portion of this posting...
http://northxkorea.blogspot.com/2009/11/decal-response-paper.html
South Korea is the regime that had was seen to really be the state lacking legitimacy at her inception; the country was dependent on American handouts (sounds a lot like the north now ?). And, Soviet troops quickly left the north and almost none, except for a very small handful of advisors by the dawn of the Korean War.
This probably didn’t change until 1980s or so, or at the very least until probably 1988 (Seoul Olympics).