Found something related you might want to check out- old schedules for Army R&D on NARA site. I can’t remember if they were under the War Department schedules or not but don’t think so since Army became its own dept. in 1947. Anyway, found references to MK and other things in them. The oldest schedules start with NN- numbers and usually have “inactive” in red next to their titles. I just remember the MK one including a note on the “volunteer” paperwork saying it was totally comprehensive and couldn’t be withdrawn.