I saw this topic so I thought I'd comment on the amount of time it takes to address this under S&W's warranty; (Thanks for resurrecting this old topic! haha)

I bought a 681 ND on Gun Broker last month. I called the seller and paid for it and asked if there was an M scribed on the crane somewhere as the photo's did not show a clear shot of the part. I was told there was no M. The seller is a brick and mortar dealer so they sent the gun to S&W at my request for the recall. That was May 17th.

I expected a length of time to pass but I now plan to call the seller to ask if they received any updates as the the status of the gun.

I figured why not let them take care of it rather than myself after the transfer?

Let us know how your gun functions upon your first range trip.

BTW, I view a good exam of an old gun by the manufacturer as a bonus to the recall issue.