He is a grey, not a blue roan. Like you said blue roans would have a dark face, as well as a black tail - he'll most likely lighten up more so and it'll be more obvious. You can see around his ears and flanks he is already whitened out more so then the rest of his body. He's a very handsome boy none-the-less. : D
well... since grays start life out dark, then gray out, it's common for them to look like this for a while. he's still young so... i was under the impression that roans didn't change color as they aged, and that they typically had dark heads and black tails. grays eventually turn white, while roans are born with an equal distribution of white/black hair, which doesn't change as they grow.
i don't know? i was TOLD he was blue roan, and that it had something to do with his breeding. he doesn't look like your typical roan though, so i'm confused. let me know if you find out something i missed!