As best I can tell, neither the Czechs nor any of the Warsaw Pact militaries used the CZ-75 or 9x19 ammo. Only a handful of Soviet troops (Special Ops types) might have used the gun operationally -- but those troops, like most Special Ops troops, could use just about anything they needed.
The CZ-75's 9x19 ammo would have created a major logistical problem for the Warsaw Pact military -- which didn't use any other weapons in that caliber. I don't think CZ-75s were even used in the Czechoslovakian or the Czech Republic police or military units until after the Soviet Bloc/Soviet Union/Warsaw Pact fell apart -- but then only after CZUB developed the 75B PCR.
I've always considered the "Cold War CZ" a marketing gimmick and it certainly got CZ some attention.
I'd buy a Retro model, which had the more-elegant look of the original 75, with the later enhancements (like the firing pin block) of the 75B, and which also used current (easily replaced) or upgraded parts and magazines. Unhappily, you just don't see them offered "used" anywhere. CZ ought to roll the Retro model out again -- I bet they'd sell out quickly.
Back when I was in the market for another CZ, the only other option that was even close was the 85 Combat, which I bought. My 85 Combat (satin nickel) was my second or third CZ, and it's the one that's I've held onto for almost 20 years.