Matt Costa - Miss Magnolia chords

All the tabs for this song so far have just been wrong.

It's an easy song, for the most part. Just basically two chords back and forth.

Intro, verse, chorus: G D


The musical interlude, however, adds a third chord, which is NOT C, but Gm.
[ Tab from: http://www.guitaretab.com/m/matt-costa/245454.html ]
So underneath the harmonica: Gm G D G


The chords, played on a mandolin, would look like this:

(strings: E-A-D-G)
G: 3-2-0-0
D: 2-0-0-2
Gm: 3-1-0-0

On guitar, chords are just normal.