Pretty sure, yes.
They can refuse to take it, but realistically what are they going to do when the car is on their property and they have the keys? If they drive it without the permission of the owner they're stuffed. Once a letter of rejection has been delivered by the seller, then they've fulfilled their part of the statute: If the seller wishes to repudiate this, then they will have to do so via the courts.
If the seller does something silly like drop the car back off, then at least when it goes to court the buyer can say that he did everything he reasonably could to return the goods. If he leaves them sitting outside his house, it looks a little more shaky.