I think $8050 was too much to pay for a gun of questionable origion. This easily could be some type of reproduction.
I can guarantee you that was an original, historic piece. I think if I didn't already have a load of them, I'd pay that (due to auctioneer premiums the final price is a good deal more than the hammer price if that's what $8050. was.) You could have a piece of history and also not worry about shooting it, they were made with great care and I've never seen one with flaws in it, and I've seen dozens and dozens of those.
Specifically, it is a French Navy "Pierrier" Model 1786. It was their standard ship's swivel gun of that era. They produced, musta been, thousands of them by many different arsenals and private foundries. These are pretty well-covered in "Boarders Away II" by Gilkerson. That book is the best source of info for swivel guns and swivel howitzers, has maybe 30 pages on that subject, with lots of photos of extant pieces and some photos of important archives documents. This model isn't rare, I think I've seen hundreds of them, and there are five here. Two are an identical pair with no marks remaining, and strangely, 2.5 inch bores and an extra ring near the breech which I guess was to tell the gunners this was the large-bore variant. The others have 2-inch bores and all come from different makers.
You can see two of these M1786 in my you-tube video on swivel guns.