Yes this seller did lie to you and did misrepresent the size of the Yorkie he was selling you and actually he lied on the documents he submitted as your post states
"Forgot to mention, I received the AKC papers 2 weeks (and 2 vet visits) after i purchased him. On the contract, the seller wrote Newton's birthdate as 9/23/11, the papers notated his actual birthdate as 9/01/11, as well. The vet thinks that the seller gave us a later birth date so we'd think Newton was further along with his shots."
I would look into whether they are registered with the better business bureau and make a complaint through them and also perhaps post a complaint on
Ripoff Report | Scams, reviews, complaints, lawsuits and frauds. File a report, post your review. Consumers educating consumers. Also if you mention the business here you can add a tag and if anyone is doing a Google search on the business this thread will come up. It may not help you but it will warn others and help get the truth out about this Breeder?Greeder?Broker?Con Artist. I would love to see pictures of your baby and we have a special thread here for the plus size Yorkie called the Teapot club
http://www.yorkietalk.com/forums/gen...apot-club.html and it is one of the fun threads on this forum. Welcome and best wishes to you.