April 16, 2012 6:52 AM PDT
Dave is playing capo 7 and a C-chord, and that equals a G-chord uncapoed. If you take a C-chord, you'll have your index finger on the C-note. Then slide the C-chord up 2 frets, then your indexfinger will be on a D-note, and if you continue up the neck till your indexfinger is on the 8th fret, you're on the G-note and a G-chord (if you have the capo on 7th).
So he plays it in the same key, I guess he just uses capo at 7 because he likes the sound up there