That's what I go by is the "pebble like" patterning on the sides, and the overall look matches what I see in pictures of other snakes labeled as granite (although I've never seen anything quite like that back stripe, but I think it's irrelevant as far as the morph goes). Also, his dad has that pebbled look as well, although faded and less pronounced. His dad has produced 3 other babies, but they have all inherited mom's reduced pattern.
We'll find out a lot more about this guy if and when his clutch hatches later this summer. Same goes for his dad, I believe.