All heavy weight A B & M forks are interchangable as they have the same tapper on the top and are the same diameter.
The plungers are spaceed further apart.
So you can fit any leg into any steering stem.
I can the A 65 on C10 legs for a while after finding a big dog with the front wheel.
The caveat on this is the damping method is differnt so if you are thinking of fitting A 65 gear then you need to swap both legs, not just one or the front will dive at an angle which is not condusive to good handleing.