Erm, surely the idea behind "RC" was that you knew one day you would have to scrap it all one day when the official version was brought out ?
I reckon you'll sleep easier (and suffer from fewer hard to troubleshoot issues) if you do the right thing.
From the Microsoft Win 7 FAQ that I'm sure you read....
Can I upgrade from the RC to the final version of Windows 7?
When you install the final version of Windows 7, you'll need to do a clean installation. So plan on backing up your data then reinstalling your applications and restoring your data.