Isn't it the "C" for Carlton?? My 72 and 76 Raleigh Proferssional have same thing. But I do not know why there are 2 "C" 's.
By the way, look the close up of Crankarm and chain ring, Campy PISTA crakset, in 1973 (if the seller is correct), they are still using 151 BCD. I wonder the pedal hole is raised? We had a long discussion about 144 vs.151 BCD, and STRADA (road) already changed to 144 in 1968, 5 years before?
Have a great 4th!
KEN TODA, High Point, NC