1860 Spencer Carbine - Odd Hatch Markings?

[Lonesome George]

Did a takedown of this 1860 Spencer Carbine, and noticed a series of 'hatch marks' on the underside ( inside ) of the Wooden Forearm and on the bottom of the barrel, behind the screw attachment and even on the  Magazine tube ( extra I mark on the tube ) that follows the rounds.

Marks are in the form of   this:    IIII  \

Any purpose or meaning?   I searched for similar markings, but mostly found Proof and Inspection marks, of course.

Photo attached, of all three parts, ( forearm, tube, barrel ) marked as described above.

Is this common?

Thanks again.

[Arizona Trooper]

Those look like typical "Old School" gunsmith assembly marks. I suspect it was put together from surplus parts by smith who built Kentuckys or Plains Rifles one at a time. You will find the same sort of marks on military arms from before the advent of interchangeable parts, such as M-1816 muskets, and on commercial Enfields imported for the Civil War. 

[Lonesome George]

Thanks.  Interesting.  Makes sense ( assembly markings ).

The barrel serial # and the receiver serial # match, for what that is worth, so who knows, about how much surplus this old iron was or is.

Thanks again.