esteban,
Different colour trays were probably used. Perhaps after the white tray ran out, they used black, or vice-versa. At one point, maybe they ordered white trays by mistake? Received a good deal on white trays, as opposed to black trays?
It doesn't matter much to me. Considering others also bought stuff new and received a different colour (My Ys Duo pack-in had a black tray, while my GoT had a white tray.). I've never heard of or seen a Godzilla with a white tray, though...