1823 Harper's Ferry musket (M1816?)

Just picked this up today. It's an M1816(?) Harper's Ferry musket made in 1823. As you can see, the barrel and stock have been altered/shortened. I'm wanting to make a 'winter project' out of it.
So far, all small parts seem to have matching numbers on them...screws, buttplate, etc. Stock is marked 'JS', which I believe is James Stubblefield. Flintlock to percussion conversion. Interesting handmade front sight/ramrod guide attached to the barrel.

To me, that looks like a conversion of an ex-service gun for use as a shotgun.

Yep, more than likely.