I'd say they would have to be pressed off and new ones pressed back onto the axle, but other than that, not a lot to it I wouldn't have thought.
I haven't had to do them on my D22 but did them years ago on an ea falcon I used to have with a solid rear axle and that was all they did. I took the new bearings and seals in with the axles and got the old ones removed and new ones fitted.
If you can get the old bearings pressed of the axle, it's not too difficult a job to do. The new ones are easy enough to get back on. Remember to pack them well with grease, they are sealed, and don't get lubricated by the diff oil. This you tube clip explains it well. Not the exact same model, no real difference though.