Welcome. I grew up on the Missouri side of KC and when I came to my senses moved to Cedar Creek and later Prairie Village
Was the gun at the Olathe Gun Shop?
'JJ' could be either Joseph Juleinond or Joseph Joiris; both barrel makers in Nessonvaux and members of
Syndicat des Fabricants de Canons de Fusil de la Vesdre.
'JF' is
Janssen Fils & Cie; a major maker of tradename guns intended for export ranging in quality from utility to very fine.
http://www.littlegun.be/arme%20belg...k/a%20janssen%20fils%20et%20cie%20gb.htmCHOKE indicates a barrel constriction > .008" and 18.3 is the bore in mm = .720" or 12g
The gun was made 1898 - 1910, and may have damascus barrels
Please see
https://www.shotgunworld.com/threads/belgian-shotgun-identification-guide.232252/"no name guns are often examples from a batch of guns made up during slow times for labeling later" is ed's creative fiction.
In 1899 alone, the U.S. firms of Hartley & Graham and Simmons Hardware bought 90,000 shotguns, rifles, and handguns from Liege gunmakers, who made guns as they were ordered, to a price point as specified, and may or may not have marked the guns with the tradename of the hardware store, sporting goods dealer, or distributors/jobbers like H.&D. Folsom.
If you examine the gun again, check if the words on the rib are in English.
There are more marks on the barrel flats and action flats.