I agree with Va.Manuf.06 , that this is a 1st model long land pattern lock, and not the early type, not banana shape.
I have never seen one of these with the ram rod as shown. I would guess that came at a later date. I see the thimble has come away from the wood as you have shown it. My best guess in the spliced woods is repairs had to be made. I can't see that well.
Looking at the pics I would have to say the piece is authentic. The shrinking in the lock mortice pretty well covers that.
Somewhere there is an error in the date. What you take for a 0 can't be..
You missed getting a shot of the brass lock plate. I can see one is there but not well. Is that flat, or rasied and how many screws are there? or if any are missing how many screws should there be there.
I don't see the butt stock being any to short either. The butt plate is correct, and the most common type thank the stars...
Oh yes, what you call a front site isn't any kind of site at all. I can see how you might think so however; and what that is, Is a bayonett lug. (Please don't tell Bill Clinton)
Aiming a musket in those days would get you flogged.
What if anything, is on the wrist escushion? Typically there are regimental markings.I would think something visable might still be there.