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From what i have read you have things figured out. The item 542490, which does not have the bayonet lug sems like it is your best bet. The hand guard is straight forward also, just depends upon what one you want to order since there are many choices. Below is a link to all of the Stocks and Handguards.
As for the length of your stock, I measured a couple M1 Carbine stocks that we have and they were 12 1/2" fom end of Trigger Guard to end of stock. The ones i measured did have the Oiler cut for the sling and oiler, so I am unsure of what stock you have. None that i know of ar like what you are describing.
FURTHERING THE LEGACY, ONE PART AT A TIME