Thanks for the shout out! But most of my knowledge was cribbed from @awe4one and his amazing research on the subject.
But yes, the NDS inserts are quite a bit more rare than the MJ's, mainly because, they were only used in books for a few years, whereas MJ's were used for a couple of decades. Also the NDS' predate the MJ's. If I'm not mistaken I also think many, if not most of the NDS' books were sold at bases overseas, which may have a lot to do with why they appear quite sparse in higher grades (8.5+).
Oh and here is my best owned example with one, by far (complete with star stamp over the "55")
-J.