You said, "This applies to all 700s, all 900s, and all 200s since at least 1983."

Not so. The 200 series didn't come standard with air until mid-85. I've had several 83 & 84 cars without, and one early-build '85 without.

In November of 1985, a/c became a "mandatory option" on 240s. That is, it was listed on the window sticker as optional at an extra price, but you couldn't buy a car without. Sometime after that (The '86 model year, perhaps), a/c got folded into the base price.