Interesting barrel lug marks

[Mills]

Yes, these are from a hammer gun and I should have said E Grade. That is interesting to learn who made the barrels. Any clue as to the other markings?

[Autumn Daze]

Mills, We believe the 6 is an inspectors mark. The 427 is in fact the last three digits of the serial number. During this period Parker Bros. employed many contractors and they were paid by quantity. When a contractor finished a section or operation they would stamp their number on the finished item. I believe in this time period regular employees were not the norm in the gun business.