Here's how these small time websites do business: they are not stocking dealers, they have very little on hand, if any. When an order comes in, they call their distributor who sends them what they've already sold you.
Sometimes the distributor hasn't got them in stock himself. Now if the dealer if honest, he emails you and offers to cancel or backorder, your choice. He shouldn't hit your credit card until he actually ships.
How do you know if he's just small time or if he's a scammer? Ask him. Does he have a street address, a phone number -- or just email? In any case, ask him a question like, is the knife serrated, black blade, steel liners. Just to see how willing he is to be polite, to get the knife out of the box and check it out.
You can tell a lot by talking to someone!