Mike, it could be a mistake. Although rare, Trim Tags have been known to have incorrect information on them.
Another possibility is that the tag could have been changed. What's your VIN? If we compare the 03C (?) build date on the tag (recheck your number. you have 03G. That would indicate the 7th week of March and that's not possible!), to the known assembly dates of the VIN's, we can see if it lines up.
A final possibility is that you have a reproduction tag. Post a picture and we can look at that as well.
Ed