stevens,
Randy,
I don't know that much about Stevens however I believe I can help a little.
I believe The rifle started life as a Stevens No. 404, "semi Military" model. This rifle as Steve mentioned used a 44-1/2 action. Several things seem to indicate in the direction of the 404.
The forearm being the extra wide, others were not.
The single barrel sling swivel (even though its been rebarreled)
The stock and butt assy.
The receiver being drilled and tapped for a no. 42 Lyman receiver sight, others used "tang" sights. Only the 414 and 404 used receiver sights.
The scope could be one of three depending on length.
#338 17 to 19 in.
#438 14 in. (both at 3-1/2 power)
#368 16 to 20 in at 6 power
Peterson probably also added the wood block on the lever. Although Stevens put wood on the levers of their full blown target rifles they were of different shape.
Just a note - the scope is on backwards but it sure a beautiful rifle.
bjm