If you can’t find one you may want to use a plastic barbed trim push pin from any local auto parts store. It won’t vibrate loose and should do the job of making sure the clutch master cylinder can’t loosen and plug the 1/8 or less inch hole. Best a luck
Does anyone know where to get the anti- rotation pin/clip that attaches to the clutch master cylinder. This is the small push-in black clip that resembles a nail and is located on the fire wall. I broke mine while replacing my clutch.