Krieghoff Mag

I just bought a 1936 Krieghof with a Haenel Schmesser mag. the top of the mag has been ground down in the middle at the top of boths sides. Is this normal manufacturing process? Also the toggel will not hold back with this mag, but will with any other mag. And the mag will work in any other luger to hold action open. The button on the right looks like it sticks out too much maybe. Any thoughts.