There has been no confirmation but currently, there is only one SATA 6Gb/s SSD and that is Crucial's C300. Most likely the SSDs Apple uses are still SATA 3Gb/s.
Probably S2, I don't think Apple is 'supporting' SATA III yet. Still testing
There are only a handful of drives out that can actually take advantage of SATA III over SATA II, I doubt Apple is using any of them for their CTO SSD options.