That photo was taken in the 50's I think.
In the late '60s he would have carried a CAR-15, I don't know what in the early '60. Might have had a Thompson, probably an M-16.. The problem was that you wanted to carry an AK-47 but they sound different, so it would have gotten you shot. Tracer color would have been a problem, too. They had some pretty tracers, I even saw some purple ones I was told came from Bulgaria or Romania.