What kind of "papers" do you have... are they registration papers if so, what are they... UKC, AKC, CanadianKC, ContinentalKC.
Also, great advice in the first comments as far as yorkies original sizes were bigger.
You puppy could have what's called a "throwback" gene. It's just a gene from your pups ancestors
Happens in Pomeranians a lot too as they used to be bigger as well. I had a purbred pom that weighed in at 12lbs.
Lots of teapots here!