No stamp just dents.
SW Recoil Plate is made for Stan Pro.
So Stock Metal is all Stan Pro.
Likely original stock was damaged and action placed in this one.
This stock shows use of only having the narrow/early barrel band.
Hand Guard will be marked on the bottom.
P on barrel is Proof fired mark.
Are you sure it says Saginaw S'G' under Rear Sight?
It's in a Split serial number block where some where marked Irwin Pedersen and some Saginaw S' G'
See Table G: The U.S. Caliber .30 Carbines - Serial Numbers