The "M" is what got me out of a no-dash. I sent mine home for the bushing and firing pin update and when I got it back....it looked like the janitor had performed the upgrades. (Not meant as an insult to house-service personnel.). Point being...a good gunsmith can drive-out the bushing and replace it with skill to make it look like a professional job. Others on the forum here debate the value and risk of sending the gun home for the upgrade. My no-dash found a new home and I have the dash-4....which as has been mentioned, seems to be considered as the most desirable example. I would purchase another no-dash if one comes-by for a fair price, but I would also look at the upgraded bushing closely if it has the "M" modification. If you find one that you can hardly tell it has ever been changed, you have found one in which somebody took the time to do it right.

My upgrade resulted in a ridge of metal around the bushing that made it appear as if they wedged an empty beer-can between the bushing and the frame.