Kenko...not Zebrakenko

I bought two bikes today a Jupiter beat and then what I thought was a zebrakenko. The head badge only says Kenko on it. That places it before 1969 right? It has a black Shimano Lark derr. Did those debut in '67? I saw the Kenko catalogue from '68 but didn't see a bike like this (they were spec'd Suntour it seems that year). Can anyone help ID it? I'm new so am not allowed to post the pictures I have of it here.