Hey, snowmman. I started skydiving in '79, went through a static-line progression with the same old 'gutter gear' that was prevalent in Cooper's day. I've been an instructor since '90, after AFF and tandems came along. In southern California, I've jumped/taught at Perris, Elsinore, Hemet, California City, And two different Tafts. Mostly at Elsinore, been back there since '04. Wasn't too active this last year, couldn't see doing tandems and not catching Covid. Did some jumps in June to keep my AFF rating current, hope I can get back to it soon, miss it dearly.
So yeah, it's always been pretty standard to have a hanging harness for emergency procedure training. I know Issaquah had one at least by '73, but it is certainly possible to just do it standing.