MSD Ignition 6013 - MSD 6-Hemi Ignition Controllers

That should be right - 88864.

The 03-05 5.7 had a different type of coil pack. Vendors sell a kit for those guys to swap to the newer coil packs, which is a single pack with two spark plug boots on it. That should be what you have, so you should be good with the 88864.

I know the FAST system has two kits because of the different plugs, they call it a 5.7 or a 6.1 kit though.

I'd let someone else weigh in on it before you buy though...