I just checked my insurance docs, it is indeed listed as a 2005 Fleetwood (based on the VIN I entered when getting the policy quote). However I know it's in reality a 2004 Ford, so that's what I'll use at the parts store.
And yes, I was fully aware of the year difference thing prior to buying, I looked at a few 04/05's and would just check the gear display to see whether it had 1-2-D or 1-2-3-D. Didn't really matter to me either way, I think the 4r100 is a tried and true strong (enough) transmission.