I'm slightly uncertain of your question.
Are you asking if they have an area in the middle of their head between their ears that is raised or if they have another issue? Can you be more specific?
Lumps and bumps can come from alot of things. No animals, in general, have random bumps on their head. Some breeds of dog have a "keel" that runs down the center of their head, but this is the natural shape of the cranium and is normal (see catahoula leopard dog, great dane, etc). Swelling on the head that makes it appear as though there are lumps can come from trauma, hydrocephalus, insect bites/stings, abscesses, tumors, etc.
See the two photos and compare them: The first is a golden, the second a great dane. As you can see, the golden has a completely smooth area atop his head, the great dane has a more "pointed" look. This is the "keel" I speak of. If the area on your dog's head looks different, you need to see your vet for determination on what it could be. Again, it can range from an insect bite to a tumor. Sometimes its minor, sometimes its major. I'd check with your veterinarian as soon as possible.
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The description made by the breeder does sound misleading.
Most well-bred retrievers will not have a "keel" unless there was some type of trauma that occurred in the past, a tumor that is growing there, etc. Sometimes retrievers many, many generations ago had another breed of dog bred into them, and therefore have a keel because of its ancestry. So, no, your dog should not (if it is truly 100% golden retriever), have this keel. I am highly recommending a visit to your vet to be absolutely certain this area is not going to harm your animal in any way. It may or may not go away, you need to see your veterinarian for this answer.