essentially, flashing a rom is "Updating" in the sense i think you had in your first post in this thread. There is no need to update anything on your stock ROM because you are entirely replacing it.
It's similar to reformatting a XP computer that's Vista capable and putting Vista on it. (Not that I would recommend that anyone do that to their poor PC.)
However, before you flash, make SURE you have followed all the steps and guides to CID (Security) Unlock your phone and have HardSPL installed properly, otherwise your Kaiser will be a $450 paperweight. SIM (Subsidy) Unlocking is NOT the same as CID unlocking, so make sure you've done it right before trying it out.
Phone: Samsung Galaxy S III
ROM: JellyWiz Beta4
- iPhone 4 on AT&T
- iPhone 3G on AT&T
- HTC Kaiser / TyTN II / AT&T Tilt on AT&T running "PHOENIX III - Improving Upon Perfection"
- HTC Wizard