As you can see, he isn't black face, though he has 2 black face brothers. This also isn't melanism, as his stomach is the normal buff color.
I'll post some pics of him, and him and his sibings. His mother is a normal grey split black cheek, and his father is a black cheek black face eumo who has genes for both types of CFW.
I know I should wait for him to molt out, but has anyone see this before in a fledgling? It looks like the cap the males have, which normally is more silver than the back, got turned very very dark. Neat, right? I hope it holds after molting

(the colored dots in the photos help me find the non-blurry ones b/c my tablet doesnt let me zoom in when i preview the photos)