Let me add a comment to the effect that since there at least appears to a be legitimate basis to assume that the Shimano Crane, under the guise of a Le Tour GT300 "Schwinn Approved" was very likely on the 1973 P-15s, or at least a mid-stream replacement, would anyone who had a thought of riding their Paramount (and speaking for myself, no matter how perfect and priceless one of my bikes may be, it must go from wall hanging or eye candy to out on the road at least twice a year, albeit for a brief ride) really want the Campy Gran Turismo on the bike? To quote Frank Berto in, 'THE DANCING CHAIN', the Gran Trashmo was arguably the worst rear derailleur to carry Campagnolo logo." I guess if I had a model that indisputably did have one (and it appears my late 73 clearly may not have had to suffer that indignity) then I would extend my normal pre-ride ritual of checking the cable, adjustments, etc and the tire pressure to changning the rear derailleur before riding, and the change it back again before returning it to the 'collection.' :-) Dave