My early 80's Chilton's (professional labor guide) shows most 77-81 W123s as having suggested specs:
Camber: 0 degrees +/-10' (minutes)
Caster: (power steering) 8 degrees 45' /-30'
Toe in: 0.08" to 0.16" (1/16" to 1/8" toe in)

Typically in the 80's we tried to tailor the alignment to the type of road crown (hi crown vs no crown). For example, highway driving (freeway/expressway had little crown) we'd go for 0 camber and very slightly stagger the caster left slightly less than right with an 1/8th inch toe in. Hi crown roads such as rural two lane section roads got L +1/2 degree camber with the R at 0; caster staggered left 1/2 degree less than right with an 1/8th inch toe in. The left camber and caster were adjusted to overcome crown issues regarding wear and pull/drift. All this assumes proper ride height (no sagging springs), tires in good condition, properly inflated and no frame damage. In situations such as you describe, we used 'offset' bolts & ball joints to try and compensate for minor frame deflection. If it was too great, we'd put it on a frame puller and try to pull it straight. Sometimes we'd find a unibody (like MBs) with one frame stub bent up. Those were an extreme challenge. Use extreme care when doing a pull - don't bend the sheet metal. BTW you always need to swing the wheel 20 degrees in & out in order to accurately check caster. Its the only way you'll catch 'set back' (bent spindle). Good luck!