We removed ours for the first time about a year after we bought the boat when we renewed the seals on the gearboxes. I do not know when the last time it had been taken apart. The only tool I needed to removed the shaft was... my finger! I literally just pushed it out.
It had been last assembled with a generous coating of Lanocote. When I put it back together I was not going to argue with success... so more Lanocote was used.
I do not know if there had ever been any previous mechanical modifications to the shaft, key or keyway.
Lanocote is not an especially good lubricant, but it is very good at excluding water, dirt and salt.
Annapolis, MD, USA