He does look kind of gray, but hard to tell if he's going to shed. If you want to see if he's going to shed soon spray him with water (tepid) and notice if the water beads up on him like a newly waxed car (not going to shed) or if his skin gets shiny and wet looking (shed soon).
He looks pretty big for 5-6 months, might be a little older, or he's a really fast grower.