Basicly yes it is the same gear and it fits on the shaft but, as the shaft key could be placed anywhere around the circumference you have to confirm the timing. Any time you use a magneto or a magneto gear for the first time, you have to confirm the timing as both the (shallow round) key slots could be placed differently. You might have to turn the magneto several cogs off. Front ignition wire on the Bosch is for the rear cylinder, same as with the Splitdorf.

Cam timing is also very important and should be the first detail to confirm as the pinion gear, new or pre-owned, or pinion shaft can have a different ground slot for the key. Tuning can be done with a offset key.

Actually, the factory placing of the marks on all gears is a bit strange in my mind since when they all are lined up, the valve springs push on the mechanism so assembling becomes difficult. If you just turn the engine counterclockwise  some 4-5 cogs on the crank, the cams are turned so there is no pressure on the lifters from the valve springs, and assembling or disassembling of the cams becomes effortless. That's the position where the marks on the gears should have been lined up in my mind.

Note that the picture doesn't show the Bosch DVR magneto at igniting point, it simply show after the ignition is set right (setting always at max advance) and the engine is turned so the gear markings line up.