First of all, it's hard to tell if Angelina Jolie had breast implants. Her bra size was a 36 C cup which is pretty big, but after her Mastectomy it's more like a B. People thought she had gotten a boob job for a long time, and if that were the case it would have immensly complicated her Mastectomy. It's possible that she had implants but got them removed at some point. This before & after picture shows Angelina Jolie when she was a teenager and when she's in her her 30's.
Here's Angelina Jolie along side Her hubby Brad Pitt while showing off her post-Mastectomy body.