Yes. Done it twice. It all depends on the year of the car and then weather or not the vehicle was also manufactured for us regulations.
For my brothers 1963 beetle, the guy just needed the title of the car (signed of course) which the border guards checked against the vin.. He paid the tax according to the ap9 (vehicle transfer form) as well as the bill of sale and then he was off!
For my 1998 gti the owner needed a letter from VW of America with the vin number stating that the vehicle met all safety and crash regulations in the us and then again he was able to take the signed registration, bill of sale and transfer form to the border. He paid the duty and was on his way.
It’s much more difficult importing into Canada.