Yes, typical. I had my eye on a Scott in an auction a couple of years ago. Hammer price: around £5,000. It appeared a few weeks later on a dealer's website at £10,000 looking exactly the same.
It's funny, my wife fulminates at the auction commission and calls it barefaced robbery, but doesn't seem to object to profiteering by dealers. Probably because usually yo don't know what they paid.