GMC Repair: A/C compressor Sunfire 2003, gm dealer, numbers change

Question
The A/C of my car is not working. The Technician told me that the A/C compressor is damage. I need a seral/part # which I do not know. Could you get the information for me, please? How I know I am getting the A/C compressor for my Sunfire 2003 and it is the compressor that I need? Thanks in advance.

Answer
well i can assure you that if you are purchasing the part from a GM dealer they will provide you with the exact compressor that you need.  However if you are buying one from a junkyard there is really no way of knowing unless you can get a part number off the old one and compare it.  The part numbers change over the course of years due to updates and what not.  SO a new part number will do you no good, you need the nubmer off the old compressor