Bearings have Two parts, at 2 points of bearing.
1) Boat side [ UHMW ]
2) Rudder side [316 Stainless sleeve]
There are no inserts for #1, if they show wear.
The Stainless sleeve can be redone and glued to the rudder.
Hopefully the boat side bearings show little wear.
They are OEM glued to the Water Tight Hull, and are in Bearing Tube that combines them.
Not much to replace, sorry.
See my post #107, page 6 for drawings and pictures...