Some have the type des­ig­na­tion RE-90 on the bot­tom right of the orange stick­er. Mine does not. I don’t know if that means anything.
Built in the 70s, I would guess.

This one was over­hauled, checked and pro­fes­sion­ally repaired by the fam­ous gui­tar shop in Darm­stadt-Eber­stadt. Everything was quite loose in it, and there were screws miss­ing. Ima­gine that!