In Iowa you can display the plates from the year of your car, if your car is over 25 years old. 1. I had the registration changed from a regular car to antique (free) 2. You must have the standard plates inside the car. If you car pulled over you can show your standard plates. I also have the laws printed out and I keep them in my car. I also plan to just use the front plate and keep the standard on the rear. Iowa never had new plates in '73 & '74. You just used '72 with a sticker.