Grew up in the early 70s in Suburban Phila. Had drills but they weren't "Duck and Cover", it was file out into the hallway in the basement and stand there. Never told us what we were doing there, we just stood there.
However, there is "NO TALKING! THERE WILL BE NO TALKING DURING A NUCLEAR HOLICOST! THOSE WHO TALK WHILE BEING IMMOLATED WILL GET DETENTION!"