"...so it was a Lend Lease rifle..." Not necessarily and highly unlikely. Those BNP stamps just mean it was sold through England at some time. British proofing has nothing to do with Lend/Lease. Didn't start until the mid 1950's either. However, a real Brit Lend/Lease M1 will still have it on the barrel too.
Most M1 Rifles(38,001 of 'em. Most in the 300,000 to 600,000 serial number range. Stock will have an “SA” over “GHS” enclosed in a box cartouche. And it'll have the “Type 1 lock bar.” rear sight.) sent to England sat in a warehouse for the duration and were eventually returned, unused, except for some issued to RAF Regm't troopies guarding air fields in the American sector after the war. The fore stock was also painted with a red band with a black .30 or .300 indicating it was not a standard Brit chambering.
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