I’m a retired police officer from MA. If you lose possession of your vehicle. And have a valid registration and insurance yo7 can swap the plates. But you are required to have a bill of sale and a stamped RMV1 form which is the application for registration. The insurance companies will issue it to you already filled out. You have 7 days to drive the vehicle you purchased as long as the insurance company has agreed to insure the new vehicle. They issue a Stamp on the RMV1 form. So the answer is yes it can be done. But it’s not just throw a plate on and drive. Yes you may get away with it but if you have not gone to the insurance company it’s a crime. You could be charged with driving an unregistered uninsured motor vehicle. The later is a criminal offense and your car will be towed and your license plates seized