Many 98 Mausers have bolts left "in the white" (not chromed, just bare steel), while others had them blued. My S37 98K has a bolt that might have been blued, but the finish now is gray and spotted (rifle is not in real good shape, finishwise). My Vz24 (fine shape) has a bolt in the white, my Yugo M48 (like new) has a plum color blueing on the bolt body.
Nearly all of the Mausers I have onwed, in original trim or sporterized have had bolt bodies in the white, usually with blued cocking pieces and bolt handles, but some have been all in the white, and some all blued.
All else being equal (and it almost never is) bigger bullets tend to work better.