I have a '91 CZ75 and it sometimes compatible. Last two magazines I ordered were current production MecGar. One fit just fine, the other not at all. I think a smith who knows what he is doing can open up the mag well in the right places.
^^^^This. I also have a 1991 made CZ-75. My 75B factory mags will not fit into the 75 pre-B, but the 75 pre-B mags will fit and function in my 1996 made 75B. My new Mec-Gar mags will fit both the 75 pre-B, and 75B. At that price BUY IT.
No need to take a file to the mag well of any Pre-B 75, or 85. Just buy Mec-Gar mags if you need more than the two it comes with.