I can add a little something, Brother Sevens.
Thanks for asking!
First, on a general, seasonal note, as it is almost two hours into Christmas Eve here on the Ridge, Merry Christmas to everyone on the Forum.
Second, on a more personal level, I know the O.P. (NavyEngineer) so, "Hi, Hank! I still have the CS9S you sold me almost three years ago and it is a fine companion to my CS40/45 about which I have written numerous times on this Forum."
Third, on another personal level I got to know Charlie Petty by virtue of a collectable I almost accidentally acquired with some other S&W "curiosities".
It was an N Frame side plate laser engraved by S&W with Charlie's name.
I related the story here:
http://smith-wessonforum.com/s-w-re...gunwriter-mystery-solved.html?highlight=Petty
Charlie was a terrific Gunwriter and a good friend to S&W and early booster to the 40s&w cartridge.
S&W management appreciated Charlie's efforts and welcomed him to the Factory on many occasions.
Charlie lived in NC and as I have some family there, I had hoped to pay him a visit.
Alas, time and tide waits for no man, and Charlie's time ended last November.
Lastly, congrats, Hank on that very special early model 4006.
My earliest 4006 wears a "TFF" prefix and is much like yours.
As I had mentioned in a previous thread, the model 4006 was the first stainless model to have a black hammer instead of silver (as was their convention, at the time) and Charlie explains why in the AR article that you posted.
Also, when the 4006 was introduced, the mag wells had sharp rear corners (as opposed to the rounded rear corners on the 59XX series) so that the 59XX series magazines could not be inadvertently inserted.
Within a few years, there was an engineering change to rounded rear corners in the magwell, allowing insertion of the 59XX series mags.
Roy Jinks has said he would look into this and try to find the reason.
Hank, if you have any other double stack 40s or 9s, take a close look at the magwells as compared to this early model.
John