I have them on mine. It is on the core support and rear trunk rail. I have a bud who has a bird and he does not have any numbers on the core support and it has not been changed. I checked on the trunk rail and it was there. I went out to his other bird he had at the time and it was the same way. Both were only stamped on the back. Called Galen and he said it was common for Birds to be missing the core support stamp.