Hello,
If you have some of these in your collections, you might want to check them against the ones at UNT. It turns out that the two I have found so far are not exactly the same as the ones at UNT--the maps are different.
Surprisingly, they are printed on paper that seems to have held up over the years. Linda Zellmer
P.S. I am having our copies scanned so that I can share the digital files with UNT.