I have a Pre B CZ 85. Are the barrels/slides different between Pre B 85's and 75"? I don't know.
I do know that the CZ 75 threaded barrel I bought for my Pre B CZ 85 would not work until I modified the slide.
Pictures of the barrels (original and new, threaded barrel). Notice the cuts down the bottom sides of the original barrel. The new barrel does not have the same cuts.
Picture of the Pre B CZ 85 slide. Notice the neck down area near the front of the slide on the inside rails. The P01 and CZ 75 Compact, and the CZ 75 SA don't have that neck down. The inside of the slide is straight, front to back. I had to remove that neck down area of the Pre B CZ 85 slide to get it to work with my new barrel.
As they say, your mileage my vary, or there may be a difference in the slides during the Pre B years or between the CZ 75 and CZ 85 Pre B models. I only have the one Pre B.
http://shop.cz-usa.com/ProductDetail/042004940102_Threaded-Barrel-9mm-75-12x28