My local gun shop sold my Ithaca Flues 20 gauge for $700.
It was in fair condition.
I'm willing to guess your gun is worth more, but not much.
The 3" chambers are not a plus.
Yours is in nice condition for its age.

Another Gr. 2 with chain damascus, which is over-priced
https://www.gunsinternational.com/guns- ... =101577890

A Flues Gr. 1 1/2 with Krupp barrels
https://www.doublegunshop.com/forums/ub ... ber=566576

After you establish that the 3" chambers appear original based on the end of the chamber wall thickness, the gun would have collector interest.
The Southern is an excellent venue to see and sell SxSs
https://www.deepriver.net/sxs-classic

I own a 1910 mfg Flues Qlty 1S with Damascus barrels and 3" chambers. I have a factory letter for this gun that shows it having those features as built. Still need to know current remaining wall thicknesses. A lot can happen in 100 years.

The Firearms Museum at Cody has Walter's records cataloged and is now able to give details by serial number.

John

1906 Belknap Hdw. catalog but likely a Lewis model with 4 pins



The Smith No. 1 with AE was $75.
$80 in 1905 would be about $2,400 today