The silkied Serama do come from the original imports, so they weren't "created" here in the US, but I don't put it past some unscrupulous breeders to cross them with Silkies and pass them off as "silkied". (There are A LOT of these because they know they're hard to find.) You're going to find that there is still a big debate over which form of Serama is acceptable here (US standards vs. Malaysian standards). There are some breeders here in the US that have taken it upon themselves to alter the original Malaysian standards to create a bird that better suits their idea of what it should look like. There are others that are trying hard to preserve the original standards, because they feel that the Malaysian standards are what defines the breed. In actuality, Seramas aren't even an official breed yet anywhere, but are in what is called a 'landrace' until there is a definite and permanent set of standards. Strict selective breeding is still going on, so many of the birds that are available are usually culls. A good breeding Serama will be pretty expensive compared to other breeds if you can find one.
Edited to say:
There is one particular breeder who claims to have a lot of different things "pop up" in his breeding stock, but he's also well known as a shyster and does cross breed his birds. I would say anyone you are wanting to buy from for quality breeding stock, ask around about them before you invest a lot of money on these birds.