Upgrade from Vista RC 1 to RC 2???

OK, here’s the short story,

I ordered, received, and installed Windows Vista RC 1 on my computer.
Though I didn’t know it at the time, I wound up downloading Vista RC 2
(5744.16). I’ve already burned the image to a DVD and it does work.

What I’d like to know is can I just install RC 2 over RC 1 or do I have to
wipe the HD?

If I have to wipe the HD, am I missing anything from RC 2 to warrant this?

Thanks,

Andrew