Model 94 spruce gun with additional markings|Winchester Rifles|Forum|Winchester Collector

This one has some additional markings ("MASS 10") that I have never see before. Does anyone have any info or theories as to what it means or what it might stand for? This auction ended this last Saturday. The rifle was located here in Oregon and only a couple hours away so I contacted the seller and negotiated a price (a bit lower than the starting price on Gunbroker) and picked it up in person this morning. The poor quality pictures did not do this rifle any justice. The rifle looks ten times better in person. It is in very good condition with all original finish–not monkeyed with in any way. The receiver blue is mostly gone with a nice bronzy patina with lots of blue remaining on the barrel and magazine. Bore is excellent. The gumwood stocks look glossy in the photos due to the seller wiping it down with a silicone cloth before taking photos. In the photos, they almost look re-varnished, but they indeed are not. They are actually about the best original condition gumwood stocks I have ever seen on a carbine of this age, let alone on a spruce gun. Anyway, if anyone can shed some light on the additional markings on this carbine, it would be much appreciated.

http://www.gunbroker.com/Auction/ViewItem.aspx?Item=361380103

Thanks,
Don