There were plenty of gunmaker shops all around the Czech part of Austro-Hungarian monarchy, even after WWI. Way more plentiful than ever in any place of the US. I will try to look up some info about this maker, but it´s not easy. Most probably J. Hanl is a descendant of Hanl gunmaker family, which dates to 18th century, moving several times along north-west boundaries of Czech republic.
The gun seems to be of 1860-1870 period, when the stepped back-action lockplates were considered fancy. They are, namely on rifles like yours. Be sure that what´s looking like gold is gold. It´s probably some custom-taylored gun made to order. Probably there are more rifles from his shop out there, but even maybe not signed-just utility smokepoles for forest and game management personell, with just one gold ring around breechplug or whole plain (yes, the fish and game management has even longer tradition in CZ). I´m no expert, but I would assume at least 1200, maybe 2000 euros as a starting bid in an auction, depending on the state of the bores.
As was said, only a bit of oil and wax is needed, maybe some 0000 steel wool on jag for the bores before sonservation. It might be shootable with mild loads, but seeing the proof marks (almost surely on bottom side of the web) would tell more.
Edit:
After looking on the figural medaillon on the tang: some landlords gave fine guns to some of their deserving foresters and gamekeepers. This might be the case...
The rifled/smooth barrel combo was (and by some still is) very favoured in hunting conditions which are around the place of origin of the gun. But richer people usually had SxS of one breed; cape guns vere mostly the "utility guns".
It would be interesting to know how it appeared in the US.