Richt: The Watchtower of 1964 page 126 first paragraph clearly states that anyone that was committing a gross sin before, during and after their baptism is void. In order to get right with the lord you would need to be re-baptised.
Was it the 1964 Watchtower? I thought that it was a 1962 Watchtower that prompted the surge of re-baptism in that year. (was there another article again in '64?)
The 1963 Yearbook, page 51, says this about the re-baptism that occurred in '62:
It also took courage for a number of others who were
not counted in with those above who were rebaptized,
evidently due to the information appearing in the article
in The Watchtower shortly before this series of conventions
on the matter of baptism, wherein it was pointed
out that, if people were not living a proper kind of life
morally and were baptized while not appreciating their
dedication to God, nor knowing fully what it meant,
they should be rebaptized. Quite a few were rebaptized
in some countries. In fact, in-one country the percentage
of those rebaptized went as high as 9 percent. Of course,
these were not counted in the numbers baptized for the
first time, as listed above. This brings home very forcefully
the responsibility that comes upon those already
dedicated to God and who are teaching newly interested
ones, namely, that, when holding Bible studies with
persons in their homes, we should not try to hurry them
into baptism, but we should give them a full understanding
of Jehovah's purposes, what requirements and responsibilities
go with dedication and baptism and be
sure that they know their lives must be morally clean
and in proper order for this important step in their
lives. Dedication and baptism are steps that everyone
must take if he is going to gain everlasting life. However,
it is not a formalism. Therefore there is no reason
to be baptized if one is unclean or does not understand
fully what he is doing.