I'm probably not qualified to give an opinion of the watch, but:
I'd want to see photos of the serial number and that it matches the valuations/papaerwork
Someone who feels the need to bolster their credentials with unprovable claims about their wealth doesn't fill me with confidence
He wants F2F delivery only but payment with Paypal which bizarrely favours you as he can't prove you received it
I suppose in the end eBay/Paypal would always side with you if it was a fake. Depends if you feel lucky. Strange that the bezel pip has aged so dark where the Tritium dial (and possibly hands) haven't?