Unfortunately you will most likely never know, the only way to tell if a pup is exactly what the breeder tells you, is to find a breeder you trust, and see all the paperwork, which they will be happy to show you. The big white patch is a bit odd, although a white medallion is allowable, I don't think you see them very often on black Labradors, although I have seen a few on chocolate/liver, and more on yellows.
Weight wise, he's very, very small, 10lbs is about 4.5kgs, and on average a pup will be between 6-8kgs when they go to new homes at 8 weeks of age, the biggest of mine was over 9kgs, so that's another niggle that would make me think he is probably not a Labrador as advertised.
The only action you can take is to report the breeder to trading standards, along with copies of the advert, and by doing that if they are found guilty of not selling pups as advertised, then hopefully it will make them think twice. But the sad reality is there are thousands of breeders out there selling pups and telling people they are whatever they want to hear, and puppy buyers do very little research, because who would be cruel enough to sell a puppy in that way. Sadly, a lot of breeders I'm afraid.
Also, just so you're aware, his claws need trimming back as they will be pushing his toes out.
