You have too restore so just backup and sync so your phone stays the same. Also make sure it's a GM because if it's just a beta you will need your device registered to a dev account to activate.
I wont be updating until the jailbreak is released and confirmed for 100%. I know that the same exploit is supposed to work until apple upgrade the hardware but I just like to be sure everything works 100% before I do...
Apple have been trying to find away of how to record if an iPhone has been jb or not. So far a fresh restore seems to work as my 7-8 3GS went back to apple ok. Lol
I read a year or so ago on patently apple that apple had submitted some sort of patent and that one of its uses could be to find out if an iphone had been jb even if the user had restored. Of course apple didn't put that in their patent application but the boffins at that site are wise to apples ploys...