A good point. If they can't tell a chinese elm from a beech, could be they have nothing to actually sell...I'd ask where they got this tree. Beech are not common in mass market bonsai.Did this person say that it was a Chinese elm? If they did, I would be really leery about buying from them.
"something that you can confirm the date on"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.