Ask for a photo of the tree with something that you can confirm the date on. For example a newspaper, magazine cover, or Olympics coverage on TV
That tree has to be kept outside, and the photo of it is sitting in someone's house. Too many questions - but you may know more about the seller and their bonafides.
Assuming everything is legit, I'd pay $80 for it. The pot is worth $20. Tree is worth more, and was styled by someone who knows bonsai.