Serial number and/or features.
You can find out what year your gun was made by having an expert appraise the gun. You can also find out by finding the model number and contacting the manufacturer.
Old gun catalogs and Blue Book of Gun Values
Blue Book of Gun Values
Blue Book of Gun Values, gun show, gun shop
the best place for gun info would be cabelas gun library.
Not made.
Proofhouse.com has sn data.
1136
Made sometime in the mid 1870's.
Most guns actually have their maker on the gun itself. Check the side of the gun.
Proofhouse.com has sn data
Try contacting the manufacturer.