The song is "Detroit has a Skyline" and the very few tabs online miss out one of the main parts of the song. The verses go E, C# and A, but over the A chord Mac plays four chords, on the 9th fret, 7th, 6th and then back to the 7th again. There are some videos online of him playing it acoustic, which give you a pretty good view of his fingers: http://www.youtube.com/watch?v=FRmwXhW7SfY
So far, I think I have the 9th and 7th fret chords figured out. It should be something like this:
So if anyone who has a better ear than me can verify that, and if anyone can help with the chord based on the sixth fret, it would be very much appreciated.