Looks like it's a 'Knickerbocker.' I have one that I restored and still shoot. Mine is not as old as yours, but i figured mine to be +/- 105 years old. Mine has fluid steel barrels, barrel indicators(?), hammerless-sidelock, 12 ga.
Yours would be older. Mine may be worth a whopping $200.
Numrich Arms should be able to give you info, as would the guys at Gun Broker.
I had a copy of serial no's and dates of manufacture somewhere. If I find it I'll let you know.