Hi Bob,
"Patchboxes and Barrel Marks, Vol. 1" shows a very similar box (#727 on page 366). The engraving is different, but the outline of the box, the 3 piercings, and screw locations are all identical. The barrel on the piece is signed John Snider.
"The Kentucky Rifle, A True American Heritage in Picture" shows a rifle with the same patchbox as above (page 83). The caption states "Signed John Snider. Location unknown, probably made in York County, PA".
Hope this helps.
-Ron
