I'm doing a neo retro build on a late 80's Rossin and putting 12 speed Campy on it. Do I need special Campy downtube cable stops or will any old one due?

Any will do...just make sure that the base of the stops have a decent curvature for the thinner round steel tubing. That said, the Campys have a more progressive adjustment, and the Shimanos seem to have been designed for larger clicks but limited adjustment.

I am sure any adjustable stop that meets the style eye test will do fine.

OK cool. Thanks for the help