Arrived today...

My SG Winchester - #1138174. WELL-used mixmaster. I reckon the barrel is original, as it is marked "W", with good lands and grooves, ME measures 2.

Other markings I've found:

Front sight - "S"
Band - "KI"
Rear Sight - Shield containing an "H"
Stock - "SA' on top of flat near band spring, no other markings
Hand Guard - 4-rivet, no markings
Slide - "7100291"(?) with "B"
Trigger Housing - shape of a building (?!) with "Inland" inset, flaming bomb with sideways "3" at gasport
Sear - "GE-Q"
Safety - "E" in circle, struck over "SS" followed by "I", with the same circled "SS" on the other side
Magazine Release - "M" ("W"?) on the button, with "E.I." on the forward surface
Bolt - flat, with "OI" ("IO"?)
Hammer - "SG"
Recoil Plate - Rock-ola

Isn't that serial number in the 1st block of Winchester production?

I might put up pics after cleaning (!), but you wouldn't be seeing anything you haven't already seen - really worn finish, beat-up stock and handguard. Still anxious to clean her up and see if she's really ready to return to action!

I also bought 10 15-rd magazines. Five with the brand "Bar AI Bar" ("AI" between a bar above and below), one "UN", one "IA", and three with "C"with superimposed upside down "T", followed by "-B". Only the "UN" shows any blueing wear - all the others are absolutely flawless - untouched.