Perhaps someone with an 04 will speak up to say whether the 04 bikes used the Glides' normal "stock radio" or the slightly fancier unit used in the 05s. If it's the stock unit you might look at Biketronics Retro Radio (
http://www.biketron.com/ ) . It's a unit that will plug in between the stock harness connectors and a variety of Sony radios.
I had some difficulty with them in that I'd bought a nice Sony head unit, XM tuner and adaptor and a few other accessories to tie it all together only to have them then tell after several conversations that their unit wouldn't work with the 05 SEEGs. As frustrating and annoying as that proved to be, however, I'd still be using their Retro Radio kit in a heartbeat if it'd just worked on the 05. Seems like a really nice kit that can give you a lot more control directly through the handlebar controls than you ever had to begin with and does so without cutting a wire or altering a connector on the bike's stock harness.
Good luck. Also, congrats that the wreck was not so serious that both you and the bike were rebuildable for future riding.