Is an OEM CD changer from a '99 TL plug compatabile with my '01 TL? w/o adapter, etc?

Anyone know. The service manager at my dealership tried to convince me that every year was different and could not be interchanged. I find that somewhat incredulous - but don't want to buy a used unit off the garage sale board if it can't be installed in my '01TL. Is he just jealous he is losing the parts business?

Thanks in advance for any advice!!
raver