The boys over at pre64win found a real treasure. I have my doubt about it being an actual USMC sniper rifle though.
The serial number does not appear in Chandler & Chandler vol. 1, but every other detail of this “US PROPERTY” marked 1941 marksman .30-06 checks out. The details include a “USMC SNIPER” marked Unertl 8x scope, which is documented to be US military issue. This is almost certainly an original US Marine Corps sniper rifle. We discovered it in an elderly farmer’s collection.