No, while both were bred as working dogs and share many qualities, they are two separate breeds with distinct characteristics.
When a Golden Retriever is born, the color they present may not be the color they keep. As a Golden matures, their coat color may change. If the puppy has color-tipped ears, the tips may be an indication of their adult coloring. Usually, the coat is lighter colored at birth than it will be after a Golden has reached maturity.
While people claim a strict pairing of purebred Golden Retrievers can produce black puppies, breeders—and the science of genetics—don't seem to agree.
A few breeders say black puppies could be the result of genes from a distant ancestor sneaking through. The claim is that a stray dominant gene may cause the Golden's black-pigment-blocking genes to turn off, thus allowing the color to present. Because part of the Golden Retriever's genetics is the gene that blocks black pigment in order to create the golden color, this theory is widely disputed.
Many others insist a black Golden Retriever must be the result of an unintended breeding or even a case of mistaken identity—perhaps the dog bred was a Flat-Coated Retriever instead. Any way you shake it, a black dog—no matter how much it looked like a Golden Retriever—could not be registered as such by the AKC.
There is a gene mutation that may cause black splotches to appear on a Golden Retriever. This somatic mutation is not genetic and won't pass to future generations.
While some breeders are working to develop a miniature Golden Retriever—a hybrid of Golden Retriever, Cocker Spaniel, and Poodle—this breed is not recognized by the AKC. 'Designer' breeding such as this is how breeds are established, so in time this hybrid may have a breed standard of its own.