Most likely you will not get a satisfactory answer from the existing Zeiss company. You asked the wrong maker. After WW2 the management and stock of the Carl Zeiss company relocated from Jena, east Germany, to west Germany and resumed production in their still existing and owned western factories, Hensoldt, Wetzlar, among them. This is the still existing “Zeiss” ompany. The old Zeiss factories in the east were expropriated by the commies and run as a VEB = Publicly Owned Enterprise. That east German “Zeiss” sold it’s products under the “Carl Zeiss, Jena” label until stopped doing so by lawsuits in several countries. You often find their products labeled “Auss Jena”. After German reunification Zeiss /west was not interested to take over the somewhat outdated scope work in Eisfeld, east. The factory tried to continue under a “Docter” label, but failed after a few years.
Your “Zeiss” VZF = Variables ZielFernrohr was made by that eastern company. It is marked DDR = GDR. So the existing western Zeiss company most likely has no Information on the once competing east German “Carl Zeiss, Jena” production.