Hi Fernando,
On my Liege pistol there is a crowned H and according to the proof mark list I attached a crowned letter was an inspection mark initiated in 1853.
As far as still producing flintlocks when better alternatives were available see
http://www.vikingsword.com/vb/showth...ght=birmingham I would suggest there was still a market for basic firearms in many parts of the world in the second half of the 19thc.
Thanks for your thoughts as always.
My Regards,
Norman.
P.S. I see Will beat me to the same conclusion.