Tough to date definitively with the proof marks.
Obviously made for the U.S. market with the 2 3/4" and 'Francotte's Choke Bore'. I've seen the 2 3/4" mark on guns imported by William Reed, VL&D & others
Nice chain damascus likely by the highly regarding Delcour-Dupont (DD) which became Canons Delcour in 1921
Non Pour Balle is usually pre-1897 but on the barrel rather than the flats. CHOKE just means muzzle constriction > .08"
It is not Nitro proved which is not uncommon on guns for export to the U.S. as it entailed an additional cost and was not required until 1924
The muzzle constriction over bore was used 1910 - 1921 (if there is no
lettre annale) but I've seen earlier guns with the mark.
17.6 mm was the bore at the time of 1st provisional proof and at 3rd finished proof the bore was 18.5 = .728" and muzzle 17.7 = .697"
The Francotte models changed in 1910 and I suspect that's about when it was imported.
If a lower grade 1910 would be 3069something and if medium 709something
The models are here
https://www.shotgunworld.com/threads/abercrombie-fitch-von-lengerke-detmold-and-francotte.393236/ Bob Beach would know the grade and he does occasionally look in on the Forum
Cornell Pubs has a 1908 VL&D catalog repro (available as a PDF) but I don't know if all the grades are shown
https://cornellpubs.com/product/1150/
