Caster angles for early 107 chassis should be 3-4 degrees. The difference side to side should be less than half a degree. The later 107 86 on took the Caster to around 9 degrees but the same rule of thumb applies; no more than a half a degree difference side to side.
I have taken this difference to greater than one degree to solve driveability problems. MB prefers a bias using camber to correct these problems and I usually use half a degree higher on the leftside for basic set-up.
I always drive a car before aligning it and look for answers to the driving conditions in the alignment.
The early 107s with the low Caster are very forgiving in their alingnment as far as pulling or drifting. I would suspect tire problems if these conditions exist. Try moving the tire side to side in the front. If the car starts pulling then they corrected for a tire problem by alignment. If no other problems exist I would switch them back and worry about it at the next tire rotation.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician