[tab10672]

   
you can drill and thread for a set screw, insert a shaft spring or make a two piece injection mold to make them identical to the original. I use springs cause these are for my own personal radios and who will ever know but me.
after you remove the original follow plastic mixing direction, add what ever color dye you need and pour        
when they dry I sand the bottom level, leave it in the mold, drill the hole for the spring, glue the spring in and that's it.    
which one is the real thing