I don't mean to resurrect the tyrosinase positive discussion here, necessarily, but that animal would have to be T+, by definition, I would think. If it were T- (a true amelanistic), there could be no black on it at all, because the tyrosine could never be jump started to produce melanin. Since it obviously has black coloration, there must be tyrosine in its system. Hence T+.
What do you think, Rich?