EV Indexes after upgrading to EV 10

Greetings

We are looking at upgrading EV 9.0.2 on 2003 x32 to EV 10 2008 R2 in few weeks time, I have read the technical guides and can't seen to find information on indexes.

What happens to the 32bit indexes after the upgrade are these fully closed unlike in version 9? I would like to  take these out of the backup schedule as the backup Window is getting bigger? Or do i need to upgrade these to 64 bit for this to happen, what are the benefits?

Thanks