As for reproduction flintlocks, I'd recommend a former client of mine, Matt Avent, of Tennessee Valley Arms in Natchez, who makes an exquisite Tennessee and Kentucky flintlock. He made a left handed version for me that is a work of art in 54 caliber.
No doubt. There were thousands of them still available and in use. But the percussion lock was the already the standard issue.... And soon to be replaced by all-in-one metallic cartridges... like the Henry, Spencer, etc. used.
I’ve got two Hawken rifles, one perc in .54, one flintlock in .50. Love shooting black powder. Such a nice BOOM and wonderful cloud of smoke.