It would be very unusual to have sway bar bushings or front control arm bushings bad. Typical wear areas at 124k mi would include lower ball joints , shocks, and the thrust links in the rear suspension. The sway bar mounting bracket also fails quite frequently on 124 chassis and the bearing at the spindle attachment in the rear end also is tough to isolate.
Another clunk can come from the differential rear mounts.
There is no need for wholesale replacement. It might be smart to replace both ball joints if one is bad but other than shocks I would only replace whats bad.
Bosch Master, ASE Master, L1
33 years MB technician