Then there are (were) also Zeiss labelled scopes made in East Germany (DDR) as opposed to those manufactured in West Germany and ones made in West Germany but for the "US" market versus those made in West Germany for the German/European markets.
Anyway lots of variants - and I have used all of these "lines" of scopes extensively (Except the US made Zeiss scopes) and they all work well.
The West German manufactured scopes (or at least labelled as West German made) function fine and have very good optics.
The East German Zeiss (Jena) are good performers and, when multicoated, are great optically (even the non-multi-coated Zeiss Jena scopes are still better than the last generation Leupold VXIII - but then I have not used the most recently released Leupolds).
The quality of fit and finish was lower on the East German Zeiss Jena scopes and they are not nitrogen purged or well sealed BUT I have never experienced fogging with them.
I doubt if the US produced Zeiss scopes will be any less capable than the German scopes - primarily because Zeiss has always been very concerned about it's brand recognition and would try to avoid a poor quality product (regardless of origin) to be distributed with it's label....
Zeiss (Oberkochen) West Germany spent a lot of money unsuccessfully trying to get the Jena located Zeiss plant, that fell into communist hands at the end of WWII, to discontinue the use of the Zeiss brand name. Since the end of the cold war the Zeiss Jena name has reappeared as part of the Zeiss corporate brand as - apparently - they are now re-united.