Peter
According to my sources, there is only the 250mm SuperAchromat, and no 350mm version. It is reputed to be one of the finest lenses that Zeiss ever made, and has never had the T* coating (Nordin, R, 1998, Hasselblad Compendium, p153). Both the C and the CF version were made in very small quantities.
As far as price goes, if someone had one of these in mint condition in its box, they could ask virtually what they liked for it.
John