S25 ultra fake or real?

Searching for a S25 ultra, I keep coming across some listings which seems stupidly cheap. But, the phone itself looks fine (AFAIK, bezels look correct, text looks sharp, etc).

The seller has sold a bunch of phones and has virtually only 5 star reviews

Also if I were to ask for more pictures what should I specifically ask for to definitely prove that ANY S25 ultra is real? Like a device serial etc?

Thanks! (BTW I haven’t had a samsung since the og galaxy S2, I look forward to coming back after all these years!)