Hello drcorc,
I just fixed my inbox and read your additional posts to my old thread. Well first thing is first, congratulations on getting an excellent and early S&W 44 magnum. When you say "didn't know what he had" I have to assume you mean the dealer you got it from and not myself because it was pretty obvious to everyone that this revolver was special and I personally thought it was special when I originally found it for sale, without the factory letter. Feel free to read through my other threads and posts if you actually wonder if I knew what I had

The dealer you bought it from did not sell it for me because I consigned it when I sold it, and so another dealer handled the transaction for me. 11 years between this thread and the present is enough time for there to be a myriad of explanations for what happened. I sold this revolver several years ago, and judging by what you said, I highly doubt that you bought it from the same guy who purchased it from me. It sold for a pretty good dollar back when I sold it, in 2015 or thereabouts.
The logical explanation for the events is that someone else must've bought the revolver, from the person who bought it from me and it may have changed hands several more times too. Sometimes people pass away, and then a gun is inherited, and then sold cheaply, and etc. Other times people sell things knowingly for cheap due to financial hardship. As for my factory letter, just because it is missing now does not mean that I kept it, as I would've had no reason to keep it, and the guy who bought it from me would've naturally wanted the factory letter, because the early ship date was a huge part of its value, and so it was included with the gun when I sold it. Interestingly enough, I had a pebble grain case with it which was only a few SNs off. I think the SN for the accompanying case was S130934 as I recall (it still had the original matching warranty card too actually), and I decided to get a letter for that case SN, just out of curiosity, and it lettered as Feb 1956 and went to some editor of some outdoorsman magazine of the time, although his name and the name of the magazine escape me.
Before you ask, I do not have the name of who bought "937" since it was consigned through a dealer. I am not sure why you wondered if you or I got "duped" as the gun is righteous, and it apparently came with a new factory letter proving its provenance. I was not duped as a seller when I sold it because I consigned it to a prominent and honest dealer who handled everything professionally. I assume the original factory letter aka my letter, was lost somehow, and then someone ordered another one.
In closing, good for you for getting a good deal on such a wonderful revolver, as we all prefer to get a deal and those victories help sustain us through the inevitable dry spells we all experience as collectors.
As Roy often says "hope this helps..."