Probably flogging a dead horse here, but.....
I might have been a year out.
According to BikePedia the C600 was only made in 1994.
I suspect that it's one of those things where bikes are released in one year, but considered another year's model.
I had a 2000 F700 that had a frame number from 1999.
Awesome bike - raced it for years - then an impatient car driver shunted me off the road and bent the back end up.
Still miss it, but decided against another due to headshock servicing problems in the UK.
Currently have a 1998 M400 - i love it - can ride it all day without any discomfort.