I am probably a dork for pointing this out but . . .

[Prussian1]

Thank you, Sir :-)

I would probably not have noticed, but I enjoy shooting with reproduction muzzleloaders.

I think the reversed lock, along with the missing sling, indicates that the artist found a very nice photo of a Charleville Musket (which is historically accurate, btw) and used it as the model for the weapon the soldier is carrying.

I have actually been waiting for someone to post something along the lines of "Well, actually there was a gunsmith in Goat Knuckle, New Hampshire that made Charleville Model Muskets with the lock on the left side because most of the citizens of Tree Rot Township were left handed. There is no sling because the famed Goat Knuckle Light Infantry Regiment had a tradition of not recognizing "Sling Arms" as a legitimate drill movement."