No,
I don't think I see it. Is it a newer phone production wise?In my experience 9/10 iPhone 6s Plus' I have seen have this blemish. I am not saying he doesn't have it but, it is plausible. My 3rd iPhone 6s Plus doesnt have it.
Photos attached. I am sure someone will claim they can see it in my imagesAlso note that I have an antiglare screen protector on.