Quoted from Cudaman:
Cheap trick, I could tell him you are going to come check it out in person. You are only 1.5 hours away! Hahaha!
It's fake. Beyond all the objective evidence, a beautiful, lovingly restored MM for $6,500 doesn't pass the smell test, especially if he's still fielding offers more than five minutes after the listing goes live.
Tell him your cousin lives in Tucson and can come check it out, with cash and a truck. He'll either stop responding, or suddenly he'll remember that the pin is actually in Fort Worth at his other storage facility (in which case you should tell him you've got a cousin there too).