An interesting story...
Here's what the company says about part of it - the actual 'proof' of configuration and purchase by an express company will require a Factory Letter from Winchester.
From 'The Winchester Book' - by Madis - pages 363 - 364.
"Many guns used by express companies and guards were merely purchased through retail outlets, rather than from the factory, and then were cut down. If this was the case, the measurements would probably differ from the factory lengths. One must often know the history of the gun in order to verify historical use of the piece, since the majority of the guards guns do not bear markings denoting ownership.
Riot guns were not standardized until late 1897; prior to this, such items were made to the customer's specifications.
In 10 or 12 guage, these short barrel shotguns were thus offered:
'The Winchester lever action 'Riot' gun is made with a 20 inch, rolled steel, cylinder bore barrel, bored expressly to shoot buckshot. These guns are used by express messengers, watchmen, prison guards, train hands, and by many people for home defense. They are far superior to a revolver for shooting in the dark, where aim is uncertain, as a buckshot cartridge contains nine bullets to one contained by a revolver cartridge. The 'Riot' gun has the regular lever action. the magazine holds five cartidges, which, with one in the chamber, makes a total of six at the command of the shooter.'
Issues prior to serials in the 50,000 range do not have the Winchester barrel address marking.
Between 50,000 and 60,000 this marking was gradually introduced."
Vaya,
Scouts Out!