Bill,
I think it would be the same story of the movement of Brown Bess' as the Charlevilles and early Springfields. The US government tended to sell off at public auctions any surplus weapons, especially flintlocks, as the era of the pecussion weapons came in. The War of 1812 stocks were mostly sold off at auction beginning post-War of 1812 and continued into the 1840's. many arsenals like Springfield and H. Ferry were ordered by the US government to re-coop the cost of repairing out-of-date muskets by selling what they considered "junk". I would suspect that both Charlevilles, Springfields would have seen the same fate as old Brown Bess muskets which had been intended for state militias. Remember the US Marines were issued Brown Bess' during the War of 1812- by their own request. So the era of the Bess came to an end in the hands of US regulars after that. Foreign weapons always took a back seat, ostensibly, to domestically produced weapons.
So take that tidbit where you wish in your search. Hope this helps.
Cheers,
Jim Chochole