I've seen some pads used to prevent slippage of furniture that can be trimmed to size (the opposite of the pads intended to make the furniture slide more easily).
I have a similar Blackburn workstand of similar vintage but the blue disk is in good shape.
Did these have a lifetime warranty? You could contact Bell Sports, who owns Blackburn, and find out.
I saw Jim Blackburn some months ago at a local pool supply store. I heard the clerk call him "Mr. Blackburn" and asked if it was Jim, and he said yes.