Yeah, I think the voltage and Max TDP gives it away (like linkin mine still says 95W even though it clocked to 3.8). Plus I'm pretty sure all the engineering samples had locked X too.
Yeah, that looks more legit. From what motherboard manufactures claim they were ES, low clocked and locked. Seems the stepping should be B0. But maybe the B0 was the first production die that wasnt stable.
Using liquid nitrogen, yeah, I've seen videos from AMD where they got to 7Ghz. Doesn't mean it's at all practical.