Just my experience , for what its worth, from
the motors I have seen, and motors I have
pictures of, the balance tube is almost always
on the 39 but I have seen just a few 38’s that
have had it, and visa versa. Parts do get moved
around over the years, if this helps you any?
Tubs.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.