How to reinstall iOS6 over a prereleased version?

Assuming you have already tried to update Over-The-Air and you are being told it is the current version. Check to make sure you aren't already running the GM/Public release of iOS6. Go to Settings>General>About>Scroll down to Version and make sure it says 10A403. If it does not, and assuming you are not a Developer, you will need to get the GM/Public release (the GM and public release builds are the exact same but you will have better luck googling a GM source) .ipsw file from the internet and install the same way you installed the betas without being a Developer. Due to forum rules that is the extent of the information I can give you but for instructions and locations of the file all can be found through google.