I don't think so. The '04-'05 MY's did not have aux inputs. Nor did we have mp3 support. There was a different part number for the '04-'05 years than the '06+ years.
I'm trying to do the reverse: set up a 06 radio in my 04 prius - add mp3 CD's and remove that anachronic cassette slot. Hope I succeed (bought the unit already). Will post here if so.