There are different sized silkies in the USA. Hatchery birds seem to run larger. Show birds smaller. Then there is the elusive Netherland red bantam silkie that was imported into this country a few years back. There is a picture of one on BYC [someplace]
Birds in the US tend to be on the larger side unless they're from a breeder. But in the UK there is a Standard Silkie and a Bantam silkie. Personally.. I would've liked it better if they just stayed a true bantam...
Did you pick it up? You might well be surprised at how little it weighs. Silkies look a whole lot larger than they are because of their furry feathers.