Some Dakotas have the 4.5" bolt pattern, others have a 6-bolt pattern.
I have no idea about the axle dimensions on these, but it shouldn't be hard to find out. They do have bigger brakes, however, and the brakes won't interchange with the A-body 8¾ brakes, even though the backing plates bolt right up, because there's a greater distance to the axle flange.
If you found a Dakota rear that's the right size, you'd use it brakes and all and probably fit a slightly smaller diameter brake cylinder. Though a proportioning valve might do the job.