We haven't done any lower end failures on the 103 motor, but based on scores of such failures in other motors, I would say that the failure often can be repaired with only crankshaft related issues.
The motor needs to come apart to see if the block was damaged; spun mains or galled piston bores. If the problem is in just the crank as often is the case then the job should be around 25 hours labor (R&R motor remove head, remove crank, remove pistons and rods where bearings have failed, replace rods where bearings failed, turn crank, replace bearings and possibly oil pump, reassemble. If it needs more than that a used motor might be the savior for those older vehicles which don't have the value to support full rebuilds.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician