The ifup-post script calls /sbin/ifup-local, if it exists, and a similar thing happens for ifdown-local. Because these are meant (I assume) as user-configurable scripts, they should be in /etc, probably in /etc/sysconfig/network-scripts. If RH wants to keep the compatibility with previous releases, you can just add symlinks /sbin/ifup-local -> /etc/sysconfig/network-scripts/ifup-local and /sbin/ifdown-local -> /etc/sysconfig/network-scripts/ifdown-local and everything should work fine in either case.
This also applies to the if{up,down}-pre-local scripts.
Closing bugs on older, no longer supported, releases. Apologies for any lack of response. Realistically, changing this now would require a) adding symlinks which b) would overwrite existing scripts. Not sure it's worth the effort.