This assumes that they did drug testing on routine physicals back then. Does anyone know how to find out which drug tests were available and were they done on the military?
I am pretty sure that random drug tests did not begin in the military until the early 80s.
When I was in Viet Nam, we were tested for Heroin use, but no one ever worried about pot use, a lot of people smoked it and when test time came around no one that I personally know of was busted for pot use because of the tests. I don't think that pot showed up, I don't know about other drugs though.
I did know people who were busted for Heroin use because of them.
Back then, I think a CO would have had to send you for a specific test if he suspected something. Physicals were routine and for the purpose of seeing if you were in good health. They weren't designed to look for drug use on a routine basis. That came later.