Karloof model shows at three scenes in the prologue. One of them is the Manila attack. Though difference is its skin is differently colored from the Karloff that showed before. Hundun had streaks of green lines over it.
Mirada previously had a concept art or deleted scene of Kaiju bones over slum in Quezon City. It looks like Karloff. by the skull.
Since Kaiju are clones with different parts Hundun is another Karloff with a pallete swap at lwast with the head and neck.