That sounds like a potential collector's item. You probably should not fire it unless and until you have a gunsmith give it a complete inspection.
No question this is a real collector's item and you should NOT DO ANYTHING TO IT -- no cleaning, no polishing, NOTHING. A bit of wood polish and shining up the metal could cost you many thousands of dollars in value.
These were made from about 1874 to 1876 or so, as I recall, and these old rabbit-ear shotguns command some very high prices, depending on the exact model and its condition.
Probably a bottom value, for one in bad condition, would be around 400 bucks. The top end is in excess of $10,000, depending on exactly what you have.
I repeat, DO NOTHING TO IMPROVE THE LOOKS OF THIS GUN !! But do locate a real, certified appraiser who is very familiar with fine firearms, or find a local museum who will help you on this. Some collector or gun store owner is liable to really take you to the cleaners on this one otherwise. This is the sort of thing they like to brag about to their buddies for years ... how they stole it from some idiot for a few hundred bucks, and sold it for bongo bucks the next day.
The appraiser will charge you, but it's well worth it in the long run.