At that point Parker was no doubt using up the pattern welded tubes still in stock. We've found a few late lower grade Smith guns with high grade damascus tubes, likely when they ran out of the 2 iron "good damascus".
And BTW "British Best" damascus was primarily 3 Iron "Oxford".
There was no meaningful difference in the strength of 2, 3, and 4 Iron crolle in the Birmingham Proof House Trial
https://docs.google.com/document/d/1...U/edit?tab=t.0