From Nikkor - The Thousand and One Nights:
Among Japanese lens-lovers, 300mm f/2.8 lenses are friendly called "San, Ni-Ppa (3, 2-8)". Nikon's first "3, 2-8" lens was born from the wish of taking sharp photos with the shutter speed as fast as possible at the event of Sapporo Winter Olympics.
(1972 Winter Olympics, Sapporo Japan)
From looking at the photograph at
Nikkor - The Thousand and One Nights the lens had a straight manual aperture control, not a preset which requires two rings. The reason for manual aperture control was for optimal placement of the aperture blade and because the lens would be used wide open to one stop closed (f/2.8~f/4.0). A preset aperture control would slow down use of the lens for sports photography. If an aperture of f/3.2 was required for exposure of slide film the photographer would set f/3.2 and shoot.
Here is a link to the article. Have a look and see what you think...
NIKKOR - The Thousand and One Nights No.11
NIKKOR-H 300mm F2.8
Dave Hartman