Ok I guess before we go any further with this can you clarify on what you are trying to do. Swap your 03 radio out with a 05???? I was under the impression that they are the same connectors and no extra harness is needed. If you need the factory harness that is in the truck and you wanna swap from a 03 to a 05 then most of the regular electronic places like Crutchfield, CC and Best Buy wont have it.
Please elaborate on what you have now and what you are looking to do.