Boot into recovery and choose factory reset, then follow by wiping the cache.
These phones have been restickered to include Android 4.3 and KNOX, but on first start it will start updating android from the cache because it is still the original stock 4.22 without the KNOX bootloader.
I just did this yesterday because my previous one dropped and the LCD broke, so I needed a new one. I already had a SIM so instead of having them set it up, I did it myself. On first bootup with the back cover still off, I saw it updating so I immediately pulled the battery to stop it. I then booted into recovery and did the factory reset and cleaned the cache. Happiness followed when I saw it was indeed Android 4.22 with SELinux as permissive. Of course from there I immediately used ODIN to perform the CF Auto Root, update SuperSu pro and install my favorite root apps
I figured there might be a few people here who might want to know this little trick.