Some additional thoughts and info:
The Campagnolo Gran Sport pedal was introduced in 1956 (steel spindle, aluminum body, steel cage). The name was changed to Record in 1967.
The Superleggero (SL) pedal was introduced in 1971 (steel spindle, aluminum body, aluminum cage, plastic dust cap.
The Super Record (SR) pedal was introduced in 1974 (titanium spindle, aluminum body, aluminum cage, plastic dust cap.
The titanium spindle was not as robust as the steel spindle and after some breakage in the pro ranks, there was a shift back to the use of the SL pedal. OMAS was the supplier to Campagnolo for all their titanium parts. Interestingly, Speedplay recommends a weight limit of 185 lb. for their X1 titanium spindle pedal.
Moreno Argentin used the track version of the SR pedal and I have noticed in photos of pro racers a good percentage of them used the track pedals on the road down through the years. It is interesting to note that around the Turn of the Century, quill pedals (cage is one piece and wraps around the end of the pedal) were considered a track pedal and the separate cage pedal we call a track pedal was considered a road pedal. I have no idea when this all changed.
Chuck Schmidt South Pasadena, Southern California http://www.velo-retro.com (Campagnolo Timeline)