Army drug testing began end of 1973 and early 1974 in Germany....perhaps earlier elsewhere.
I know because I was a young enlisted guy in Germany who had to (among other things) label the pee bottles.
I was still at the Academy and grad school in those years. I just don't recall being drug tested during UPT, or fighter upgrade -- but, I really can't remember that far back about the physicals, they did a lot of blood testing, etc. -- all I know is I had nothing to worry about!
Not in a "real" fighter squadron until mid 76.
I still have "surprise" drug tests -- compliments of the airline I fly for.