window moulding question

hey
got a 97 gt
the back door has the mouldingbetween the main window and the smaller window(goes up verticaly)..its the metel strip
and its rusted and is stickin out and looks like shit
so my question is can i have this just replace, how hard is it to dissemble the door to remove this trim and replace it. im guessin it might be a dealer only part..
let me know