Per Wilson, that gun was made in 1900. FWIW, that means it is not legally an antique under federal law.
It looks like it is nickel plated; a factory letter should say if that is the original finish. At least one screw appears to be a replacement, but that is a minor flaw and easily corrected by using a new properly shaped screw.
Limit cleaning to removal of dirt and any crud that is in the barrel and chambers. Do not use an abrasive of any kind. Be careful with the grips; old stag grips can be very brittle. Do not disassemble the gun unless absolutely necessary for repairs or cleaning, and then leave takedown to someone who knows those old guns and has the proper screwdrivers.
If there is any documentation available (letters from the original owner, documented stories of how great granddad shot that bandit with it, etc.) try to get hold of it and preserve it. Even the sales slip or an original box, holster, and so forth add to the value.
Jim