Thanks for trying Jerry, but I just can't be sure as to the pattern.
I think the pattern is similar to this 1877 Quality 2 which is 3 Iron
The plot thickens however, as the barrels appear to carry the Diamond P mark found on some c. 1880 Lifters
1879 Lifter with Laminated Steel barrels
Courtesy of Brad Bachelder 9-2010
The diamond P remains to be an elusive mystery. What we have learned so far is a few commonalities. This mark appears on lifter and top lever guns, made around 1880. We have identified it on laminated, twist, and damascus barrels.
It generally is stamped on the right tube next to the extractor rod cut. In a few cases we have seen it on the forend hanger.
Quite often this mark is partially removed by machining. This leads me to believe it might be an acceptance mark, stamped after the initial barrel and lug assembly. Final fitting of the extractor rod clearance often removes some or all of the mark. The absence of braze in the mark also tells me that it was stamped after the lug brazing.