A problem with replacing my left taillight cover

Hi, I have a simple question.
I have broken my left tailight cover, the plastic cover by accident. The lights are working. The dealer asks a price of $260 to buy both left and right covers.

I find that I can buy the cover from internet. There are plenty of them. However I donot know if all of them fit my own car. For instance, this one: http://www.amazon.com/2004-04-06-CHEVY-MALIBU-LIGHT/dp/B0012HF6A4/ref=sr_1_3?ie=UTF8&s=automotive&qid=1230859032&sr=8-3
It is exactly for 2005 malibu base model.

But it does not have PartsLink # or OEM#. I donot know what are these numbers and whether they matter. My question is whether I can simply buy it. Do all of them fit my own car?

My car is 2005 malibu, base model.

Thanks.

I'd go to a junk yard and get one for a lot cheaper. They also know what can be cross referenced.