Based on the replies, I see that I know so little about the subjects that it was probably a naive question on my part. I have, as usual, been educated, though, as it occurs to me from suggestions that the Fowler Kibler makes is neither the English trade gun I was thinking of, nor the French Fusil, but a trade gun of English design, looking more like the French. Thanks for the patience.
I'll mention this for your amusement. On these slow, quiet Sunday evenings, I think that if I had a smoothbore flintlock, I could hunt every season in PA with the same gun, except, of course, archery.