Someone dropping the ball at SA, or perhaps a do-it-yourself conversion with M2 parts, including stock, ordered from DCM? Ser. no. 14587, with matching electro-penciled bolt, brl. date 9/27.

Brophy noted (p. 287) "some modified rifles show crude workmanship...and inconsistency in the size of stamps used and placement of marks on the receiver." Campbell says virtually the same thing, and speculates that non-standard conversions might be the work of USMC armorers. Instead of "II" on the receiver, this one is over-stamped with "2" because, being also D&T, there wasn't sufficient space for the additional "I."