I just pressed the last two of mine today. I had one fail a couple years ago. Two weeks ago a second one was changed on the way to the races in Kansas city. I had a hot hub that turned out to be the brake magnet. I had the extra bearing along so changed it at that time. I found a shop with a press to change the bearing. I did the rest of the work of removing the hub and drum and reinstalling.
I disassembled the two that I removed today. A bent screw driver punch used on the inside of the inner race will punch out one side of the bearing and the seal. The other side can then be punched out.
These are on a 2002 unit with the 50mm bearings. The grease was stiff and black. They were due for replacement.
However, I think after looking at these bearing that they could be disassembled, cleaned and new grease packed into the bearing. New seals would be desirable.
That's what I plan to do with these and they will be come spare bearings.