Apparently, the earliest Tournament Grades had the "Black Diamond" in the grip as well as the Trap and Pigeon Grades.
2-14 Model 1912 Folder 01.jpg
2-14 Model 1912 Folder 03.jpg
Winchester revised this February 1914 folder adding that the "Black Diamond" would be omitted from the Tournament Grade.
2-14 Model 1912 Folder 02 Tournament Grade Ebony Diamond omitted.jpg
In the 1915 folder the Trap Grade is listed in all three gauges --
1915 Trap Grade.jpg
while the Tournament Grade remained 12-gaauge only --
1915 Tournament Grade.jpg
and is pictured without the "Black Diamond."