Check to see if its a LSD mercedes differential or if its a GT differential. AMG installed GT differentials.... not mercedes LSD differentials.

Also, ASD is a hydraulically regulated differential. It will have the same oil canister that SLS equipped cars have in the engine bay. when it detects wheel spin, it will lock up.

ASR is from what I understand something to do with braking when it detects a difference in speed. I don't believe any W123's had ASD or ASR even offered as an option.