I removed the locking flag on my NM66 when I tore it completely down to have it re bead-blasted. I left the flag out when I put it back together due in large part to the hubbub of people who despise it.

I didn't like the small notch gap on the left side of the hammer with the locking flag omitted... there was no way to make it look like something wasn't missing due to that empty space. I re-installed the flag, function tested it, and it's never caused me a problem.