I wouldn't be surprised to learn that there is technology developed by the military in the '60s that we still don't know about.
Possibly, but much of it may have been supplanted by better technology. One of my hobbies is to learn about interesting alternative past technology. There is a gal on youtube called "Fran", and she's always coming up with technology from the 1960s and playing with it and discussing how it works. I believe her channel is called "Fran's Lab", or some such. I've watched several of her videos, but she's not the only one that discusses old technology. There are quite a few others as well.
I love old technology.