Seems very far-fetched. Logistics have not been a strong suit of the Russians throughout this war. The movement and supply of these troops would be a tremendous logistical challenge and I’m sure support elements in the North Korean forces are also very poor. Once in theatre, the North Korean troops would need be deployed as battalions (or Battalion Tactical Groups [BTGs] in the current parlance). Given the well-documented weaknesses in the Russian army within the junior officer corps, and the obvious language problems, it’s hard to imagine just how direction would be provided to the Korean troops. I’m not sure such a deployment would add any combat power or really be of any constructive use at all.
There’s no mention of this development on the best web-site for following the war: https://www.understandingwar.org.