Job #32-610 in the W126 manual clearly shows that the upper end of the leveling strut has two bushings. These appear to be similar to the rubber bushings you'd find on any standard shock absorber where you have two rubber donuts that the shock shaft passes through. One is situated above and one below the mounting plate. The leveling strut would have to be removed in order to replace the bushing. The job lists specific part numbers for the upper and the lower bushings, which leads one to believe the bushing are replaceable without replacing the entire strut.
I have no idea how close this info is for a W140, but should be similar enough for the W124's.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.