Drew;
If you open the Picture Trail from the link you posted, down the page a bit is a W Richards marked gun with left side lever which looks just like mine. Another picture shows the top rib marked Laminated Steel which mine also has, though it does appear to be plain twist. Then the picture with proof marks which looks to be the one you posted in this last posting.
Above the picture of the side lever W Richards is the following;
W. Richards
The 1886 catalog from John P. Moore's Sons in New York listed "Clabrough's Make" W. Richards.
Note that the proof marks shown predate 1887 which I believe is too early to have a Crescent connection, though it does seem to have been imported by Folsom. This appears to be the exact gun I have. I have no idea as to when my Grandfather acquired it. He had it as long as my Dad could remember, but he was not born until 1910. He later bought another W Richards gun but it has Belgian proof marks. Although neither was taken care of over the ensuing years it is obvious the Birmingham gun was originally of higher quality than the Belgian one.
While the bores on mine are heavily pitted they currently measure just under a 13 (.710"). I seriously doubt they have ever been honed. My Dad's older brother, a bachelor farmer, had possession of both these guns for many years & he simply did not take care of them. He used the Birmingham gun until the stock cracked & it became un-shootable then switched to the Belgian one. He was not a hunter or shooter as such, kept them for predator control on his farm. Which ever one he was using at the time was always loaded with "High Brass" #4's IE 3 3/4-1 1/4 loads. I tried to tell him these loads were simply too heavy for these old guns but I might as well have been "Dribbling" water on a duck's back for all the good it did.
He had the Belgian one out with him one day & saw a section of fence which needed mending so laid the gun on the ground. When he finished with the fence he forgot he had the gun & left it. When he did miss it he thought someone had come in his house & stolen it so it went undiscovered for about a year. Needless to say it was a total rust heap & ruined. I now have both the Birmingham gun as well as the rust pile of the other.
In my Uncles own words he was "As Independent as a Hog on Ice" & I will have to say he did a very good job of describing himself, but I loved him anyway, in spite of his faults. When he spoke of things in which he was truly interested, as Tractors, their equipment & use it paid to listen to him. Guns were simply a tool with him & not needed often so didn''t get much of his attention.