W2000 server to W2003 server question

I have two W2K domain controllers that serve my network.

I also have one W2003 server within the network.

I want to use GPpolicy to control aspects of IE8 (inprivate) and that
needs to be on a 2003 DC.

I'm assuming that I need a 2nd 2003 box to take over backup DC duties,
as you can't mix the 2000 and 2003 as DC's.

Is this all correct?
I's love to leave it in place as it has been bulletproof for many
years, but we really need that policy in place.

Any input from the group?