He's sure a cute little guy.
I don't think he's yellowbelly, the mustache and nose spots aren't that unusual, but he's sure a little looker. I can see why he caught your eye.
He could almost make me think a low quality vanilla, he's got a little something that makes me think he's not quite normal, but not quite a morph. I'd be tempted to keep him if I were you, just to see how he looks as he grows.
Gale