Here is another 1901 F with a similar pattern; 4 Iron "Very Fine" Damascus which should be on A and B grade hammerguns. The patterns are a bit messy compared to yours however. Did you refinish the barrels?
So was Hunter Arms using up higher grade damascus tubes in the transition to fluid steel?
When "rough forged" or in-the-white the pattern is very difficult to discern so maybe the error was when the tubes were paired in Belgium?