Thank you, everyone, for your responses.
Drew Hause's info regarding Glasgow Uni's special archives collection of the House of Fraser (and thus, the A&N C.S.L.) records was exceptionally helpful. I gathered all the information I knew and that all of you were able to glean from my photos, and sent the archivist an email as per their instructions. Here's what they returned this morning:
According to the Army & Navy registers of stock and sales of guns that we hold, the gun was originally purchased by Mould Esq, on 06/09/1890 for 17 pounds and 17 shillings (our ref: FRAS309/4).
Note that the purchase date is September 6th, 1890, not June 9th, due to the British practice of writing dates as day-month-year.
Ms. Rogers from the archives kindly sent along some extremely clear photos of the record books, including information regarding the order date (14/11/89 or November 14th, 1889) and the maker. In this case, I was far off base. This particular example was made by Edwin Charles Hodges, and is one of two consecutively numbered London sidelock non-ejector hammer guns made for A&N C.S.L. by Hodges. This would have been around the time he worked out of his home workshop at 8 Florence Street.
The price paid, adjusted for inflation, equates to
£16,679.75 £2,971.97 in today's money, or
$22,317.76 $3,977.85 for those of us on the west side of the pond. (Edit: Google was smoking something serious when it gave me the earlier numbers)
More info on Hodges from the website run by his descendant:
https://hodgesgunmakers.yolasite.com/ec-hodges.php The list of his clients is quite extraordinary. Atkin, Grant, Lang, Army & Navy, etc. He is known to have actioned the pair of Grants that Queen Victoria presented to Prince Albert (the future King Edward VII) for his birthday and Christmas in 1870.
Not a bad pickup at all, if I do say so myself.
Edit: The records show that it is a "D" grade gun by the A&N C.S.L. standard. I was able to find it in an old catalog of theirs from around the same time as the gun was sold.
![[Linked Image from i.imgur.com]](https://i.imgur.com/l9DSiGN.png)