1908reeves, Gday again,
Would strongly urge you to buy a copy of Charles W. Pates book the Smith&Wesson American Model. It has a wealth of information regarding the early model 3 American and variations. Available at Amazon for about 50 bucks plus postage.
Would be interested to know how you came across this piece, gunshop, auction etc just for my personal interest. When you get the bug on these early models, it bights you hard like an addiction.
The FJ inscription, I wish for your sake that provenance can be proved, but it will be a long task, suggest you start at the Frazier Histrical Arms museum in Louisville Kentucky which houses some of the James gang stuff. They did use a great variety of weapons including Colts as well as S&W Russian models, and Schofields as well as New model numbers threes.
Your revolver may have been shipped to M.W. Robinson of New York City, however another by the name of Wexel & Degress also dealt in these rimfire Americans.
Would urge you not to have the gun refinished, a general clean-up etc yes, suggest David R Chicoine of Old West Gunsmithing would be able to help you there, he is an expert on the old Smiths.
Best Regards and good luck.
Bob