i would say between 1965
and 1967......The Tonal 1 seemed to run from about 65 to as late as 76, with improvements. Yours is differently one if the first, and a way you can tell is the on off , reject is a round dial type....the later ones had a flip type switch, and in some of the last were re designed to make the back end of the tone arm seem much more "High Tech" than it really was...lol.....
Do you have the Porta-Fi units with it?