Hello,
to know if the Jena plants made any 3,5 Tessar with the Contax mount after 1945, I'd better check in Kuc's "Auf den Spuren der Contax" vol. II.
Inherited from my father, I have a Contax-S SLR with both the CZJ Biotar 2/58 and the Tessar 3,5/50. It's years since I've used both lenses for the last time, but I remember that the Tessar gave very fine results, kind of sharper than the also very fine Biotar.
I've called today a friend of mine who uses a western Zeiss-Opton Tessar 3,5/50 with his RF Contax: he confirms that it gives excellent results and he likes it a lot, besides its already mentioned, relative rarity (but this latter aspect is more interesting to collectors than to users like us). I need to shoot a film with my one, as soon as possible.
Best wishes,
Enzo