Here's a 2 on a 1, any more info guys. Mike.

Mike,
This must be a Winchester which originally left the factory as an M2.
During wartime production Winchester spend to much time on development of there own selective fire system until they reached the moment that they had to produce and deliver M2's. In order to fulfill there contract they overstamped there allready produced M1 receivers.
Regards, Andreas (The Netherlands)