The North Koreans are a very heavily armed group, overall. Aside from the military, there are several 'reserve' and 'militia' organizations, numbering in the millions.
(The Red Guards Militia, the Worker-Peasant Red Guards, and the Red Youth Guards, etc.)
Most of the militia units are local, and have light machine guns, grenades, anti-aircraft guns, etc. Military training is extremely common, usually on Sundays. A town will hold their own local training, starting at adolescence with the Red Youth Guards)
And all are useless. These militias and the regular army are just a prison camp without walls. Their mission is to not overthrow the government. Military effectiveness is not a factor.
If so much of the population is heavily armed, one would think collapse would come quickly - triggered by almost anything - once discipline cracks.