Thanks for everyone's help. But a quick question that I cannot find an answer for online. The receiver is clearly marked SG and SAGINAW but the upper receiver is marked above the chamber is marked:

U.S. CARBINE
CAL. 30 ML

Why does it have ML and not M1icon? I am clearly missing something here.

@Frank, thanks for the info and offer for help on the stock. I am going to try to get my Brother who repairs furniture to take a look for me.