I received my new tank and I didn't realize that the decals come with the tank. Even though I have an 03 and the decals are for an 04, I think I will keep them on. They will definitely last longer as each side consists of two small decals, one on top and one on the bottom. My old ones only bubbled in the middle.
They have discontinued the 03 tank, but as you already know the 03 and 04 are the same. Not sure why they discontinued the 03 part number when it's the same tank and the decals are still available.