Bob Burns has most of Minor's stuff I think. At least the TMP/p2 stuff. As for material that Paramount bought in the 60s ... boy, that'd be something if it survived, wouldn't it? Uhura's earpiece was still around a decade later ...
I dare to say that you'd to be blind and stupid not to realize that Mike Minor's paintings do have some objective value. That's the kind of stuff that usually never ends up in a garbage can, right?
As we have just witnessed with the WNM phaser rifle, some things just spent a little longer in some kind of time capsule before being rediscovered (and Jules Verne's first story "Paris in the 20th Century" spent 125 years in a time capsule if I remember correctly). I just hope to be still around when Mike's artwork shows up...