Pitting on the Mauser bolt face is fairly common. Pitting on the bolt body is not common. Normally, if the bolt body is pitted, the receiver of the gun is also corroded to the extent that it is unserviceable. Where is the pitting on your bolt?
I would not turn down a bolt body. Shaving .008 from the bolt face and shortening the firing pin is possible if the pitting is on the bolt face, however. This can be done if you are fitting a new barrel or requalifying the existing one. Otherwise you will increase the headspace too much.
If the bolt body is pitted too much to polish out with normal polishing wheels, it is time for a new bolt. Headspace MUST be checked and reset if necessary when you replace the bolt.