No matter what capacity the Compact pistol mags were, does the law limit you to Compact magazines only?
The full sized CZ75 mags will fit/work in your CZ Compact.
You can buy a plastic base that fits on a full sized CZ75 9MM pistol that makes those mags "pretty" in a Compact pistol.
They don't make the 16 round full sized magazine longer. What they do is slide over the bottom of the mag. tube and extend upwards so there is no gap between the bottom of the Compact pistol frame and the bottom of the magazine. I use them on my P01 pistols (for pretty magazines.)
The UG P01 has the 16 round magazines with that plastic base that extends upwards.
The black P01 had the standard 14 round Compact pistol magazine.
How do you prove a magazine is "pre-ban?" No dates on them.
You can buy the complete magazines (probably not want you want since they are new.) Or you can buy some old 16 round magazines (not sure how you prove they are old) and buy the new bases from Greg Cote, LLC. I've done that a couple times to make 16 round "pretty mags." for my P01s and CZ75 Compact.
The 16 round, 17 round, 18 round and 19 round magazines (if you can prove they are pre-ban and your state's law doesn't keep you from using CZ75/SP01 magazines in a CZ75 Compact/P01/PCR pistol) will all work in your Compact, they just stick out and look funny and you don't really want to carry concealed with a one of them adding an inch or more of length to the frame you're trying to hide. I carry with the standard magazine in the compact pistol and carry the longer magazines as spares/back ups. If I've run my pistol magazine empty I don't care if the spare makes the pistol look funny, and I'll be glad to have the extra rounds as well.