I personally believe that the Auto-version will come with "driver shift selection" as GM puts it.
Every new vehicle that has the new 6L80 auto-tranny has this feature. even the Malibu. What is up for speculation, IMO, is how Chevy will implement it, whether it be like the CTS(tap up/down shifter), or like the Vette (paddle/thumb shifters)
But Mindz is absolutely right, no official info has been released other than the dour: "...choice of auto or manual..."
And Welcome!