TNTom

I've been doing some research as too what radio harness adaptor i need for my Alhambra, I finally found the correct one which is apparently for the amplified version meaning i have an amp somewhere in the car from factory, I did a bit more digging and it should be right under the radio, but I have a storage pocket right under the radio and nothing else, I also have the CD changer model 2007, with a 2004 date stamp on the top. There's no changer in the rear where it should be. So i'm kind of confused as to if i actually have an factory amp at all? If so where is it meant to be located