Are there different output shafts for the 2x4 and 4x4 models?

Someone told me they were different but when I cracked open my Alto clutch manual they show only one output shaft but two different tail shafts...one for 4x4 and one for 2x4. The 4x4 tail shaft is basically a spacer to attach to a BW 1356 for i.e.

Anyone care to enlighten me?

Thanks!