One must also remember that stocks were a stand alone purchasable item from S&W. I have blister packs of stocks from the 70's that are intact and have never been on a gun. Who is to say if they will stay that way for the next 100 years.
Folks do it today so I am sure that gun enthusiasts 100 years ago did the same thing. Guns with pearls could have gotten damaged and a gunsmith removed them and sold them to someone.
Unfortunately as I have said before, sometimes we just don't know what we don't know......
