IMHO it is pretty hopeless to find rings to fit the Krieghoff bases. First, these proprietary mounts were not made any more since at least 1945. Further, most scopes "forgotten" by liberating GIs were remounted in the 1950s using claw mounts. The few Krieghoff mounts I have seen so far all had no real clamp-on scope rings but old-style half-rings soldered to the scope's steel tube.
As both bases appear to be wedged into dovetail slots cut into the rib, for practical purposes I would do it another way: Push the bases out of their slots, left to right. Measure their thickness and note any difference. Store them safely away for collector's sake. File new bases to fit modern rings from bar stock, perhaps Weaver or Talley style, and fit them into the existing dovetails.Any gun tinker worth his salt should be able to produce workable bases, a good gunsmith may even be able to shape and engrave them in a way, so that the change is close to undetectable.