I'll have an update when it comes out, but the SEC office has already said their will be no competing games for the two CBS games (3:30 and 8). All other games will be noon or earlier kickoff.
I'm guessing the two games will be some combination of Alabama at Florida (which is a near mortal lock for one of the CBS slots), Texas A&M at Arkansas (at Jerry World in Dallas), Auburn at South Carolina (SECCG rematch), and Mississippi State at Georgia. Just looking at that list, I don't see any way CBS picks the UGA game over both of those other two games without ESPN doing some serious late season horse trading to get the other games.
So, I'm going with Noon on ESPN.
UPDATE: Noon on Fox Sports South, per the SEC.