I just received the plug for my M-625 and I have a couple of questions. Mine appears a little different than the one shown in post #14. Mine does not have a flat spot on it and it came with a small "U" shaped retaining spring.

So do I use the "U" shaped spring to hold the plug in place or do I use the fork and spring that held the original lock cylinder/cam?

Also, do I have to remove the flag? Can I file down the locking nub that engages the hammer and leave the flag?