If you do order a letter, keep in mind that the probability of getting a big surprise as described is very low, especially so for a common revolver model made in large volume. Chances are it will letter as having been shipped to some S&W distributor, sporting goods store, etc. Shipments made to a specific individual are unusual and approach rarity. And even if shipped to an individual, it is unlikely to be anyone famous or notorious. And the letter will not provide any information at all about the gun's later travels or ownership after it shipped.

There is nothing wrong about lettering a S&W ($100). It will tell you the date of its shipment from the factory, the destination of its shipment, and possibly details about it such as whether it was blued or plated, barrel length, type of grips, etc. But if there is something highly unusual about it, such as being a special order, that might show up also.

Just do not have high expectations that you have lucked into a treasure, because that will very probably not happen. Sort of comparable to buying a lottery ticket. If the gun letters to have been shipped to Clyde Barrow or Alphonse Capone, then you can cheer.