I have dozens of them from the source. None of them have too much white speckling. The only for-sure thing that they need to have is the marbled foot. Mine don't always have yellow tips depending on the light that I have them under, but if they do have a marbled foot and yellow tips, then they are very likely CSBs. The yellow tips can always come back if I put them under more blue light.
They also should come with some lineage.
I would not buy one without a marbled foot. Period. Without yellow tips, only if the seller is super trustworthy.