I don't think it's a YB. I'd be more inclined to cross my fingers for it proving to be a Chocolate, or even a Sable...But, I hope for every nice dinker I come across to be a Chocolate, I've developed a bit of an obsession with them.

Mandatory Obligatory Disclaimer: Bottom line, you won't know anything for sure until you see his offspring...Don't count on Yellow Belly though. I just don't see it.