2003 6 Disk HU vs. 2004 6 Disk HU

[2k3Expy]

I have noticed the 2004 model offers the SAT and AUX buttons. I really would like to have the AUX button my 2003 HU doesn't have. Are they swappable?

Here is a link of what I am talking about with the 2004 model.
2004 HU CL listing

Ebay listing of what I have in my 2003

 

[GAINMOB]

call the dealership and see if it was an option...if so...should work unless your VIN isnt wired for it