The serial number, 19522, would place it long before the Invincible. While there is no production card for 19522, those on either side of it shipped in
May 1912. It may have been a second or something pulled from inventory and made up for the Panama - Pacific International Exposition in 1915 --
Panama Pacific International Exposition Blue Ribbon 1915.jpg
DIANA is somewhat similar to Billy Gough's personal trap gun, 20175, which cards as an A-Grade for W.H. Gough in December 1912.
20175 left side.jpg
20175 watertable.jpeg
Interesting that DIANA has the rebates and fancy-back, which first show up on some of the SPECIALs Gough did for the Panama - Pacific International Exposition, see Tom Kidd's article in
The Double Gun Journal, Volume Eleven, Issue 2.