Your correct, this is a common working gun probably assembled with parts from different sources. We think of the term "cottage industry" as a 60s hippy thing, but this was used in Europe in the 1800s by the weapons industry. I was totally unaware of this until one day sitting in the office at the Museum of the Fur Trade with Charles E. Hanson, Jr. Charley used the term several times, I'm lost and ask why the "cottage industry" term?
He explains that in the late part of the 18th century into the early part of the 19th century in Europe the different towns became suppliers of gun parts as well as other goods. One group were cutters of wood, dried and sold for stocks, while another town made locks, and so on. Another group would assemble the parts into a complete product. This was "cottage industry" at its finest.
Your in Philadelphia, Boston or a southern town, have a hardware store and want guns to sell. You contact an agent here in one of the bigger cities like those mentioned. If you buy a current number of his wares they will put your store name on them.
A good example is the "Tryon" weapons, Tryon was located and still is in Philadelphia PA. They're a hardware firm, dist. of equipment, etc. When Charley used this as an example it brought back memories from 20 years before. My family had a power outdoor equipment shop 20 miles out of Philly. I use to go to Tryon to pickup "Lawn Boy" lawnmowers as they were the dist., while waiting for our order to be filled I would look into the office of Joe Tryon and could see a pair of long guns hanging on the wall. One day I asked about them and was invited into the office to look at them. Joe told me they had been hanging there as long as he could remember even as a little boy (he's now in his 70s). He said they were one of their first ventures at the "cottage industry" items available from over seas.
Your gun is probably a very good chance one of the "cottage industry" items available to dealers world wide. Look at Dixie Gun Works Antique catalog or one of the auction houses that deal in antique weapons on the Internet and you'll find ones that come real close or match yours. This will also show you a current value on your gun.