According to the parts book, the front axle is the same. number for B, C, & D.
Spindles for B & C the same. D is different.
King pin for B, C, D all the same
Brake support (backing plate) for C & D the same. B is different.
Brake shoes for C & D the same. B is different.
Drums and hubs are different for each, just to complicate things.
So according to this, you could leave your axle on and put B or C spindles on it, as long as you use the complete brake system, drums, backing plate, and hubs for the spindle you are putting on.
Clear as mud? Hope this helps.