I have never seen an original one that could be removed because I am thinking they are moulded on.
One way to restore them is to build up the worn areas of the rod with weld and file it back round. Then re-serrate the knob for deep knurling to make the Judge "happy" followed by re-polishing the knob, ...then encapsulate the knob in liquid plastic to protect the finish when you have the rod sent for cad plating. (lotta work for little reward IMO!!)
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