Well, let me start by saying I like it. I have a similar gun in 20 ga although yours seems to have monobloc chambers.
On the barrel flats you will likely find a crown over an oval with letters ELG which means barrels were proofed in Liege, Belgium, and from the style was likely made between 1895 and 1905. Almost certainly made in Belgium for the American "hardware store" market which is why the English lettering. Probably barrels are laminated "twist" steel. Value is going to depend a lot on whether it is fit only to be de-commissioned and hang on the wall ($175), or whether it is deemed okay for low pressure loads by a gunsmith. In great, shoot-able shape its a $400 value. A lot less if 2.5" or 2 5/8" chambers rather than 2 3/4. A lot lot less if you take off the forestock and find the barrels wiggle against the receiver. Not a lot of collectors for these unlike with early American or English gunmakers. Many have been shot loose and are off face from shooting modern high pressure loads. Depends on how much use it has seen and yours seems pretty clean. A cowboy action guy might want it to cut down to a stage gun length for black powder loads and this would be a reasonable use for your gun.
At least, that's what I think.