That is a nice example, although I am a little skeptical that the case colors are original.
I noticed a Flues Grade 1 1/2 with Damascus on Gunbroker with what IMO would be original finishes. If you prefer the floral engraving pattern, this one does not have that, but it is advertised to have 2 3/4" chambers and the dimensions are more modern.
https://www.gunbroker.com/item/925094518
I have no connection to the Gunbroker seller, as noted before, his prices are generally on the upper side and his guns are for sale forever, I do however admire some of his items
Stan
Flues 20 Gauge
Hybrid Mode