No ! they were differnt hardnes for doing stencils, for memeograph machines.Like
Mitch Fixit has some repair chops, so this is believe-able: Some of the colored platens were meant to have different harnesses for doing stencils.
via https://www.facebook.com/groups/TypewriterCollectors/posts/10163612704804678/
Typewriters had switches to allow the typewriter to use different portions of the typewriter ribbon. Some were utilized to differentiate between colors on multi-colored ribbons (typically between black and red) while others allowed the use of the top or bottom of a ribbon to get more use (economy) out of them. Many also made the ribbon inoperative so that the type struck directly against a sheet to allow for stencil cutting.
p. 12
Typewriters, Stencils, and Carbon Copies by Tim Covell