Answer
Cars equipped with cd changers have a different lining inside the boot to include a bulge on the left side, with an access door. this bulge will house a bracket that holds the cd changer and dvd sat nav system (if so equipped).
if your car did not come with cd changer, you will have a regular lining without this bulge.
if you wish to put in a cd changer and retain the factory appearance, you will need to buy the extra parts mentioned above.