Have a look at these for similarities in the lock style particularly the use of the flintlocks frizzen spring for the nipple protecting safety.
http://www.gunbroker.com/Auction/Vie...Item=274778472
Scroll down the page on this link http://www.horstheld.com/0-prussian.htm
http://www.middlesexvillagetrading.com/P1850PC.shtml