1982 Fairmont buildup

I recently acquired a 1982 Ford Fairmont with the 3.3L I6, Power assist steering, and the CA emissions system installed. As far as the engine goes, its running (mostly) like a champ. chasing vaccume leaks through the CA emissions system was a bear and a half; the previous owner was a tinkerer, however it was quickly obvious that they had no clue as to what they were doing, as I had to quickly replace the voltage regulator, as they had wired a new alternator backwards, and neglected a ground wire. today I was going to tackle the high-idle issue, and came across something that I didn't expect: the idle mixture screw was not where any of the videos or pictures said it should be; instead there is just a deep hole; with nothing in it.

rebuilding an older car like this can be fun; but not being able to even use my local autoparts stores to get a replacement, or finding a rebuild kit that includes the screw was outside my expectations.