For a moment I was wondering why you took the complicated approach, but then realized that the button had to be removed from the inside since it had no front slot...
Myself, I'd like to have an M2 with a lens release button shroud like the M3 has, I'm always fiddling the camera and the M2 button is so easy to push... I worry someday my Summilux 35/1.4 will fall off...
Leica II (1932), VIDOM, Elmars 50 & 135, Heliar 50: the nickel kit
Leica II (1942), Minifinder, Canon 28, W-Nikkor 35, Elmar 90: the chrome kit
Ricoh GXR Monochrom