M1 Carbine IBM "AO" Receiver Question

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I took another look at the OP's post. He should post a picture of the marking on the receiver. I've never seen an instance where the "IBM CORP" is stamped in front of the rear sight. It may be a one-of-a-kind or "home work".

My humble apologies to all -- I checked my M1 again and saw that I was in error, it was only the s/n that was stamped ahead of the rear sight and not the "IBM" stamp. And yes, it does appear to be an arsenal s/n stamp as the numbers are not in perfect alignment as is the original factory stamp. As mentioned earlier, having the type III barrel band and the adjustable rear sight definitely indicates an arsenal re-build.

I will try & take detailed pictures when time allows.....

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