Would having a missing alignment camber washer on a control arm on either side mess up an accurate reading of adjusting the torsion keys?

That stuff has to be done correctly by someone who has made his "learning mistakes" already. Even then, weird things can go wrong.

We bought a replacement control arm from the Dodge dealer. Our mechanic installed it, but could not get it to align properly. It turns out to have been a LEFT control arm getting installed on the RIGHT side. The factory-stamped part number on it was for a RIGHT control arm. The dealer initially said it couldn't be wrong, so we told him, "Order another one." He said, "It'll cost you." We said, "If it's wrong it won't cost you or me anything. Chrysler Corp. will pay for it."

We hope that the Dodge people learned how to avoid putting wrong numbers on parts. The trick to getting them right is to make the number-stamping operation an immediate follow-on to the final forging or grinding, rather than something that happens days later after the parts have sat around in a bin.

Similar care and good procedures will make someone a good mechanic who won't omit a crucial part in reassembly. Look at the situation with head bolts on an engine. Does it matter which bolts go in which holes when bolting the head back on? (You and your mechanic had better have that one right!)

Torsion keys relate to torsion bars, the springs that support the car. You can adjust the preload on the spring with torsion key changing the ride height. Cars with coil or leaf spring have no such adjustment normally. When you install the shims that set caster and camber you will effect toe. So set ride height with torsion key, then caster and camber with shims or eccentric adjustments, then set toe. Then recheck. If it was close to start with then the recheck may prove good to go. A missing 1/8 washer might be like 1/16 of toe. It moves one control arm while the other stays put causing half the motion at the spindle and the tire rod is close to center line of spindle so it's about half the amount.

According to a forum post (perhaps not accurate), "change the camber on the knuckle you get a HUGE toe change." I would imagine that changing one would automatically change the other. Thus, to properly align the wheels, you'd have to go through the alignment process a few times until all readings are close. Missing a washer would cause a major change in the camber, so likely cause a change in the toe-in (torsion keys, I presume).

Missing parts always make proper operation difficult or impossible.