As everyone should know that has read this board for a while, the 2N was the "War time" version of the 9N. The model change was to indicate that the "War time" (9N) tractor was NOT the same as pre-war. Rather it was on steel wheels, had no starter or battery, and thus, had to have a magneto ignition.
The 2N magneto is in the picture on the right. Note the adapter so it could attach where the distributer would. There is obviously a right angle drive in the adapter so the magneto could be mounted up and out of the way of the fan and belts.
The fellow that posted the picture said that the magneto on the left would replace the distributer on a side mount distributer engine. (I think... CRS you know) Clearly if the shaft was long enough and the gear correct, it could be substituted for a distributer, but ONLY on a '50 and up 8N. But then some people have switched the front cover on earlier engines to get away from the front mounted distributer, which would then allow Paul's magneto to be used.
No intention to "correct" anyone just "enlighten" in the spirit of the reason this board is here.