Deering says, of their long neck models and its tuning, "If you want more flexibility in your range, this banjo is for you. It can be capoed at the third fret and played as a regular 5-string in the key of G or left open and played in the key of E."

This implies that they recommend that you tune the 5th string to its normal G, and the others to an open E chord, as opposed to the open, G - then with a capo at the third fret you are playing a standard G tuning. It makes sense.