it looks like he has a white spot on his neck.
This quote is from the gliderpedia on breeding colors
"Patterns:
White Face - A glider that lacks the dark ear bars.
Mosaic - A sugar glider with
various white patches & markings. There are several mosaic variations: White Mosaic, Ringtail Mosaic, Piebald Mosaic, etc. "
I would say a "white tipped mosaic"
Congrats, He is beautiful!