"...an all original..." There's no such thing as an "all original" M1 Carbine. Winchester only made 15 of the parts including the receiver. Everybody and his brother all over the eastern U.S.iconmade Carbine parts. Most of 'em didn't use any marks.
Go here and scroll way down to the bottom and read the 'Worth Noting' paragraph. All the menu links work too.
The U.S. Caliber .30 Carbines