Just to jump in here, Fences has a 64 bit version because otherwise it wouldn't work on a 64 bit OS.
It installs into program files (x86) as some parts may remain 32 bit which don't need to be 64 bit because they run for short periods only. But the bit that does the work (I.e. the Fences) will be 64 bit when installed on a 64 bit OS.
