Thanks guys. I have heard before that Mecgar makes the CZ75b mags.
After loading up the new mags and doing some side-by-side comparisons, i am even more confused. The font on the two 17 round Mecgar mags i ordered earlier this month is a very close match to the font on the indented mag i just purchased (but not to the non-indented mags), however most of the indented mag's numbers (5,10,16) are on the mag's left side (side facing my face when in the pistol) with only the "15" on the mag's right side while the 17 round Mecgars are numbered on the other side, right side, only. The other non-indented mags (flat base plate, OEM-looking) are numbered on their left side only. The mags that came with my used CZ and the three non-indented mags from this weeks purchase match each other in all respects, font, capacity, etc.
They all seem to hold their listed capacity. The spring on the indented mag seemed
a tiny bit softer when i loaded it, but that may have been my imagination.