The way his post is worded means the picture he's responding to is the first time he's seen a PL-15 seeker. If he had seen prior images, he'd have said something like "didn't think I'd see a PL-15 seeker outside of a vault."
As I already stated, guy is a bit vague for the sake of liability, so you're entitled to interpret his words differently.
However, how do you explain the confidence and specificity of his assessment of the ?
Buddy, you obviously didn't pay attention to the war thread as it was happening. It was debunked by the Chinese side, sourcing the image to Chinese academic literature from years ago. I'm just pointing it out, in case you're unaware (which you obviously are). You're positing a contention which has already been debated and settled on this very forum. You are late to the party.
The point isn't so much where the image of the PL-15E's AESA seeker came from, but that it's already a known item to the American authorities, and how that could have possibly came about.