Darned if I Know.
I suggest looking around town for another 82GP, also should be the same for similar years in the Cutlass, Regal, Malibu. If the A arm looks the same, then the orientation of the shafts should be the same. As for the washer, that was a shim, it was supposed to go back where it came from. If there's a corresponding washer mark on the A arm shaft or where it mounted that's just plain lucky. Otherwise, when you get your front end realigned your alignment guy will figure it out. By the way, let him know about the possible washer misplacement so he doesn't spend an hour trying to figure out why your GP can't go left (or right).