If they will be releasing to Sprint at that time too, then it was extremely covert. So covert that it never went through Sprint's LTE labs, even. Which isn't unprecedented, because Apple devices don't go through Sprint labs for advance testing. However, all previous Samsung devices have, so this would be the first to go through covert stealth mode.
We will have to see. I would love for it to happen. However, I am skeptical that we will see the GS3 on Sprint before Fall.
Robert