I'm buying a non-registered chocolate lab that is supposedly full-blooded but all the puppies have white blades on their chest. Am I being lied to about them being full-blooded?

Not necessarily. The Breed Standard states clearly that a small amount of white on the chest is permissible.

Why would you want to buy an unregistered labrador?  Are the parents registered and have they been hip scored and eye tested???????  If not, you could be buying a liability not an asset!!

And it could cost you a lot more money in the long run.

One of Daisys last litter had a tiny bit of white on her chest which her new owner says has now completely disappeared.They were fully kc reg and the breed standard does state that a small bit of white is permissible, but be v careful if you're buying an unregistered dog. 

yeah, if you are going to purchas and unregistered dog, why don't you just save an unwanted puppy from a shelter.  it might be a mix-breed, but so is my dog and he is fantastic and lovely.  if you get an unregistered lab, you can't really be sure it is a pure bred.