2 months ago, I bought a baby leo from a reptile shop, he was sold as a 'normal/high yellow'; yesterday, while I was cleaning his tank, I discovered he has grown a lot of orange on the side his body, all the way to its snout. My question is, I know tang babies are born with orange bands, but this one, he has absolutely no sign of orange when I got him, not even very yellow; could this be just a temporary thing, or is he turning into a tang?
This is how he looks when I got him in mid-May:

And this is how he looks yesterday:


