I have a 13t if that could be any use. I'm not sure if it's original campag, but it came off a mavic cosmic with campag 8 speed freehub body (the original type, not exadrive), so I imagine it will work. It only has 7 of the 8 splines, so might well work on an exa-drive body too, although I'm not 100% sure on that... I also have a few other sprockets from the same cassette, but I need to check how worn they are and what sizes.
let me know if you want it
Thanks for the offer but it does need to be 12 tooth as the next sprocket up is a 13. The type I need is the flanged one that is the last sprocket on before the lock ring.
Chas Roberts in Columbus SL, Vitus 979 (Full Campag Veloce), Vitus 797, Olmo (Fluted tubing), Fondriest MegaCarb, Ridley Aeron (modern winter bike), Olmo Competition