The shape of the lockplate of Dana's gun is still more curved in the traditional "banana" shape. This form was already obsolete in the 1730s. Also if i look closely at the name on the lockplate i would swear i see GoyeT with a t (or a l with a scratch trough it?)
This thread covers some of this as well.
http://www.vikingsword.com/vb/showthread.php?t=18292