Hi there, he is a real cutie, and yes that's either just color or it may be that he's shedding as well. You got him mad enough to show off a little blackbeard as well.
What a little cutie pie! LOL
He did sport a little bit of a black beard while you were poking & prodding him. That just
looks like possible shed or even pigmentation changes that do happen when they start to
mature.