The rifles were supposed to be marked on the barrel, receiver, and bolt lug. The softer barrel steel took the stamps well, but the harder receiver and bolt did not. IIRC the first to be dropped was the bolt. They continued to whack at the receivers, even after the dies were blunted so much that the mark is just a blotch.
There was nothing in the proof regs about marking the sight cover. Those are US marks that were on there when the rifles went overseas.
Information
Warning: This is a relatively older thread
This discussion is older than 360 days. Some information contained in it may no longer be current.