I believe the dating codes mentioned above are for the Strada (Nuovo / Super Record) cranks. I'm not sure if they crossed over to the C-Record cranks as well. Engraved logo is earlier, the black printed logo is the later. VeloBase also has a lot of the Campagnolo catalogs posted (but requires a login to download). Registration is free however so that's a non-issue. I'm fairly sure Campagnolo dropped the "Corsa" Record for just "Record" around 1990 or so.