re: Duck and Cover
I was born the year after you started first grade, and I did do those drills in the early 1960s. We were not instructed to hide under desks, however: we were all sent down to the school basement, where we were to huddle against the outside walls. At the time, I rather thought of myself as Dorothy in the Wizard of Oz.
The building had a Civil Defense symbol posted on it. I wondered whether we would be joined by other people from the neighborhood, and where we would put them.
My children did tornado drills in school that resembled the Duck & Cover things. The one was obviously derived from the other, though I believe the tornado drill procedures are older. I had never experienced a tornado drill, though, not until I moved to Pennsylvania.