Some you do, some you don't. The set I had I was able to run the pedestal studs without a washer and grind the inside of my valve covers flat and they worked with no problem. Brian
12V yes you either have to machine the pedestal or grind the valve cover.
24V nothing, just install.
CR you need to grind the back of the spacer plate at number 6, when you install it you will see which one it is.