Update
I just bought a P-07 on sale for $410.
The dealer researched, then tested P-10C magazines, they fit perfectly.
In fact, the package is marked P-10C and P-07.
They seem to be identical to the 2 that came with the gun.
It seems CZ didn't discontinue the P-07 mags, they just merged them with the P-10C.
Yeah we know all that already. The problem is the P-07 only mags had a base plate that conformed to the grip frame of the P-07. The P-07/P10-C mags have a base plate that conforms to the P10-C but doesn't fit all that nicely with the P-07.
When I read your comment, I examined all my mags.
Two of them have a perfect fit.
I had to examine the other two very closely. They do have a very slight overhang.
The difference is very tiny. Without reading your comment, I would never have noticed.
I can certainly live with that.
However; I have a plastic bag in my gun case with two mag extenders.
I can't tell if they just add length to the mag, or if they are +2 extenders.
They do look like Mec-Gar +2 extenders.
I don't know whether to try and figure them out, or just leave them in the case.
But, I won't complain. It's a much better gun than my Glock 19, for $410.