I think I see it on the 75 mags. They have an elongated depression, about in the middle on the 10 round, and at the bottom for the 14 and 16 round mags, with the 14 round having a longer one ending higher. The Mec-Gar 18 round has no depression. If it's the same, that would be too large to drill out, so hopefully the P07 mags are different.