MB was kind here. In the widest part of the motor there is a P/S brace bolted on top of a large screw with a stud built out of it. This screw is designed on the inside to prevent the chain from being able to move a tooth or more. The crank gear is similarly protected. Thus it is almost impossible to change the pump to crank relationship. All you need to worry about is the crank to cam relationship.
The only thing I would be sure of is whether that bolt is the original one with the stud protruding. If you remove it you will find that it has a rounded protrusion extended about three eights of an inch beyond the threads. That is the part necessary to keep the chain on the gear. It comes so close to the chain/gear that the chain can't get far enough from the gear to move.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician