upgrade from 32 bit to 64 bit within same postgresql major release (e.g. 8.3.x)

hi

I'm looking at upgrading a server from 32 bit Centos 4.4 to 64 bit Centos 4.7.  I'll also be going from Postgres
8.3.3/32bit to Postgres 8.3.9/64 bit.  I know that if I were upgrading from 8.3 to 8.4 I would need to do a dump and
restore.  But I can't find documentation that tells me whether I need to dump/restore when just moving from 32 bits to
64bits... 

Do I?

Thanks