There's a saying, something about things seeming, "Too good to be true."
Can't remember exactly how it goes, but . . . a conference between you, the seller, and a knowledgeable representative of the Department of Motor Vehicles with all relevant documentation present might clarify the transaction.
Without such transparency, I wouldn't touch this one with a vaulting pole. Why would anyone market a commodity at a fraction of its value? Would you buy $ 100 bills, on sale for $ 50 each?
Better question: Would you SELL authentic $ 100 bills for $ 50 each?
Your money; your choice!