Here are three photos from a recent eBay auction (Item number: 310174417074). Excellent photos by eBay seller "driftwares" and for this reason perhaps deserving of the very high $129 final bid.
http://i368.photobucket.com/
http://i368.photobucket.com/
http://i368.photobucket.com/
These show a Simplex retro-friction shifter set with less commonly seen "feet" at the bottom edges of the lever arms. These were supports for slots which held the ends of the internal springs. Most models had slots cut into the upper sides of the lever arms, just above the mounting bolts, which serve the same purpose.
Placing the slot at the bottom minimized the potential for moisture and dirt to fall into the spring chamber. Perhaps a nice idea, although not as graceful in overall appearance.
Would this be the very earliest version? Can anyone give the correct production date for this particular variation?
I would love to see any catalog images which show this minor feature. Perhaps Daniel Rebour observed these in an early trade show and presented them in "Le Cycle"? My earliest US catalog illustrations show the "final" version - although forged with the same lever arm design pattern.
I believe the retro-friction levers were first introduced in 1973, although they were rarely if ever seen in the US for perhaps another 2 years.
BOB HANSON, ALBUQUERQUE, NEW MEXICO, USA