My first "real" camera, an Exacta, had a Zeiss Jena 50mm on it. It was a wonderful sharp, contrasty lens that started me on a long (and expensive) love affair with German glass.
I believe that Jena was the East German side of the company after WWII but if I'm wrong, I'm sure someone more knowledgable will correct me.
You are right. Those are East German produced in Jena