War Baby ( Roughly $50) and The Carbine Club Newsletters are the best information available. You must be a member of the Carbine Club.
Carbine Club sticky at the top of this page. There you can find a Data Sheet that can be printed off and mail in. Data sheet is very useful for part type ID.
U.S. M1icon Carbines, Wartime Production (6th) edition is handy for quick reference and at gun shows, about $20 + or - ).

Your stock has the Standard Products over RWH post WWII rebuild stamp on it. Standard and Underwood were the only 2 prime makers to receive post war rebuild contracts, along with numerous Armorys and depots.

Have you noticed if there are any markings in the your stocks' left rear slingwell?
Possibly OI, HI or other markings?
The stock has the late style cut out inside for the M2 semi/full auto selection kit.
And your sear marked BCE (?) Are you sure? I don't recall this marking. Possible it could be a lightly struck BOB.

Charlie-painter777