There was still some co-operation between CZJ and Zeiss West Germany until 2 or 3 years later. So if it says Jena it's an East German lens. The two halves of the company still hoped to re-unite in 1950, and CZJ were still making lenses for the West although there were some quality issues. Zeiss (West) used the name Opton for a time to show these were there own lenses although it's thought a few were still from CZJ but passed through Oberkochens quality control first.

I have a 1952 (approx) 150mm f4.5 CZJ Tessar T coated, and it's a very good lens, the same lens was supplied to Linhof until the East severed the ties between the two companies.

Welcome to APUG BTW