Of course this build is targeted at the international version, not the stateside versions. Since the processor and RAM are different, not to mention networks and carriers, it is quite possible that it will destroy your phone in a fury of hell fire and brimstone. Well, maybe not that dramatic, but chances are it will mess things up.
It should however, give our fine developers something to work with to build up some great new Jelly Bean ROMs for the S III variants though. We will be keeping our eyes peeled for those. Until then, if you feel lucky, you can head over to SamMobile and pick up the current leaked pre-build release. Let us know how it goes if you give it shot on your prized S III.