Chris,
I can't come up with any technical details at the moment, but the cam in LB1120 (a 1913 'TT' model) is just marked with a 'C'. Some years ago - when the bike belonged to Trevor Phillipps - I compared the cam to a 5B, and it had higher lift and longer opening.
For those who dont know the history of this bike - it was bought (new) by the Stroud brothers of Reigate and raced on the board tracks around London. It was then laid up until Allan Phillipps bought it (from the Stroud brothers) in 1960. Allan rebuilt it and used it in numerous Club events until his untimely death in 1972 (including leading the parade at the 1967 Diamond Jubilee TT meeting in the IOM - where it was also sampled by the likes of Bill Ivy, Phil Read and Agostini) - then Trevor (and eventually, Janine) took over the riding. I wouldn't like to guess how many thousands of miles it has covered - but it is still a quick 2¾ - easily capable of 60 mph.
Next time I have to look in the timing cover, I'll put a degree plate on the cam and expose it's darkest secrets!
Eddie.