Go to your local Caddy dealer, and give them your VIN. They search thier computer, and find the part numbers of what was on your car, when it was brand new. That is how I got the numbers for my struts.
Man, I must have a damn cool dealer. I did not buy my car from them, but they have been extremely helpful. I have never been denied info from them. I got the strut part numbers from them, over the phone. Thier phone number escapes me at the moment, but here is the dealers info.
Are code for them is 732. Just call information, get the number, and give them a call.