I'm saying that in 2000-ish, Army was teaching 1,2 low-ready; 3 high ready. In 2003, high-ready became the norm when stacking on the door.
Not because someone would grab a gun, but whacking it into a doorframe or #2 sweeping #1 as 1&2 split. I personally know of at least one AD into the concrete at JRTC's live fire shoothouse because of the low-ready transition into doorframe.