Spectacular gun
The Crass & Lewis era catalogs listed the No. 3 as "Fine Damascus" and No. 4 as "Very Fine Damascus"; Crown steel was also listed for both.
I've seen Chain on a Crass & Lewis Gr. 3 and both "Washington" (no stars in the scrolls) and "American Flag" (with stars) on a Lewis Gr. 4, and "American Flag" on this Lewis I believe is a Pigeon No. 2
Jay's gun is a 4 Iron "Oxford" Crolle.
I tried to enhance the image and the arrows indicate the ribband edge where the scrolls were squished (how's that for engineering exactitude?
) when the edges were "jumped". The arrow on the far R shows the straight ribband edge weld rather than the 'zipper' welds between the rods
Flues No. 3 were "Chain Damascus" and No. 4 "American Flag"; Krupp was also listed for both at least c. 1915.