No, I have never seen the need for it. I worked part time for the distributor that received the gun, I was in their warehouse when it was received, and when it was taken out of the shipping container from the factory, it was placed in my hands and I paid for it and it went out the door with me. That is a pretty solid “ chain of custody”.
The fact that it came with TH, TT is not anything significant to me other than a deviation from the norm. I was a armorer for this distributor and saw thousands of S&W revolvers, and quite a few deviations from the norm. The fact that 58’s came from the factory with TH, TT’s, have been documented with letters ( like one above this post) so they obviously did ship that way.
I have owned, carried and shot this revolver for 40 years, spending money for a letter confirming something I already know, does not make much sense to me. This gun is going to be with me until I don’t need it, doubt if whoever ends up with it next will care about a letter, if they do, they can letter it.