http://writingball.blogspot.com/2014/09/mystery-machine-specialized-lc-smith.html
see another potential example: https://old.reddit.com/r/typewriters/comments/1oincod/can_someone_tell_me_what_yearmodel_this_is/
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