Sounds like a shutter swap, as the Mess Ikonta 524/2 used only a Pronto(r) or Compur shutter with this model and had either a Novar or a West German Tessar.

I don't recall Zeiss Ikon using East Germany parts with this model, which was among the last of its folding cameras.

Regardless, as long as the shutter is running properly and the lens is clean and collimated, you should get very good photos.