It isn't a champagne piebald because it isn't a piebald. The white has nothing to do with what morph it is, the genetics are what determine what morph it is. There are lots of ringers out there, some have more white than others, none of which are genetic though.
Until you can prove this a piebald through breeding (unlikely as I don't think Brock has a bunch of hets laying around he didn't know where hets), then it's a ringer.