i dont think there is a paint code for the stock ex 16" alloys. and you could prolly measure the circumfrence of the caps by taking the diameter of them and multiplying it by 3.14... if you dont mind me asking, why are you looking for a paint code for the wheels?
i hate how the stock koup wheels say kia. i got the k badges and now i want a blank center cap for the gun metal 16" rims. i planned on painting the new center caps to match the stock wheels.
i call a dealer and he said all he would have are stock ones and only part #s, not sizes