I have a plain old 16ga Sterlingworth that I bought on-line from a seller in PA. It was made around 1923.
I sent away for the letter, just because. The information that came back was fascinating. Seems the gun was originally sold to a sporting goods store in Havana Cuba.
It really doesn't make the gun worth any more to any one except me. I like to think about the hunting trips it may have been used on.
In my case it took a bit longer to get the letter back. No big deal, I was happy to be able to find any information.
The only on-line factory information, freely available, that
I am aware of, is from Marble arms for the little game-getters.
http://www.marblescutlery.com/gamegetter/index.aspEven then you may not know who actually purchased the gun. Seems for many famous buyers, Webster Marble had the gun listed as being sold to him.
I hear the Colt factory information has become very expensive. In comparison, the Fox letter is cheap.
Pete