Sam Tehrani is a colleague of mine, but he's based in Sunnyvale. It's legit. I completely understand any concern surrounding the need for the SSN number. That's been a long-standing concern with customers when completing pre-shipment warranties on CPUs in GPUs.
For the warranties, and shipping a physical product, it was never AMD that required it. It was the US Government (aka - Homeland Security) that required it. As for a simple coupon-code to get BF4 for free, I'm not sure where this falls under for needing the SSN, but I would certainly e-mail Sam and get his feedback on the reason for needing the SSN.
At the very least, I can 100% tell you that e-mail address, and Sam Tehrani are completely legit.
AMD Customer Care
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