The "Back Action" flinters date to 1815 made in America flint locks. Davy Crockett owned one he died in 1836. The posted rifle appears to be a Southern rifle with the long "Lollipop" tang. I would say it was originally an American flinter. The "Back Action" flint lock were know for their superior accuracy due to increased lock speed. They were popular on Squirrel and match rifles.
Many amateur gun enthusiast believe only front action locks were used during the Flint lock period.
This rifle was made in Jefferson Co. Ky. possible 1820?