I have a '39 CS and it is an outstanding driver. I've been driving it for 26 years. Ford built 3,561 Convertible Sedans in '39, the last year for that body style. As others have said, if you have the time, money,etc, and the parts that are unique to the CS are there, l'd go for it��
I thought they made a CS in '40? Maybe it was called something else.