Bill, in corresponding with you, your gun is a Smith Baker gun from around 1881-82. The dates you see are patent dates and if you go to the Home page, scroll down on the left hand side to History. It opens to the right and you will see Patent Dates. If you click on the patent number it will open and you can read all about what the patent was applied for.
It is a Quality A, the lowest graded gun made at that time.