Don't Laugh, Serious Question

So here's the deal: I sold a buddy a motherboard of mine (Gigabyte Z390 Aorus Master) who lives in Las Vegas, Nevada (I live in N. CA). I got a 3rd friend that claims that my buddies IP could be held by the motherboard lan unless he does an IP release and therefore he can possibly have the same IP address I had (different ISP and state).

I told him the hardware mac address would be the same since that isn't changed but the IP address would change since his ISP would assign a completely different one but he argued the IP address could remain the same unless he did a manual release of the IP. Keep in mind, we're talking strictly about the motherboard w/the built in ethernet here, not an entire PC.

Please give your thoughts, preferably network engineers or IT guys who do this daily.

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Thanks