Sorry, I mis-read your original post as to body type. My original comments about cluster construction wouldn't apply to 140 chassis cars. The problem likely could be corrected internally, but I'm pretty sure those clusters have no internal pieces available through MB.
We just repaired a cluster on a C280 with a sticking speedo meter movement and none of the pieces were available through MB or VDO. The whole unit for that car was near $800. We found a used meter movement from one of our VDO suppliers.
The only long term problem I can think of would involve spiking the odometer prom from a bad ground circuit. Since the factory repair to either condition would be the same, I don't see any problem with ignoring it.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician