The car would be a 2003 so, assuming the vehicle was first registered (ever, in any country) in 2003. Many new cars lie in stock unregistered over the new year. They still get registered to the first owner on the date, and hence year purchased by the customer through the dealer.
You will however have to pay the VRT at the current market value of a 2003 registered car.
It is unusual however that you would find out that the car was in stock in Ireland unregistered in 2002. How was this?