I spent my time during the early to mid '70s in the Army Reserves. In '74 we were at Ft Bliss for summer camp. At the time I was a Cpl. When walking into the PX a Spec 6 was coming out. He snaped a smart salute and, as a naturally curious person, I looked over my shoulder. No one was behind me. So, I returned his salute. Found out later that he was respecting the
hard rank since at the time about the only E4s wearing Cpl stripes were graduates of SE Asia.