They are there...I have an '04. They aren't easy to find as you are probably expecting to see the anchor just exposed. You will need to look for the little sticker as they are hiding behind a tab in the upholstery. It is possible the previous owner removed the sticker or sticker wore off.
For the middle captain chairs, they are located near the plastic part (along side where wheel well is) behind the seat. You will see a perforated area probably no larger than your thumb. I needed to cut 2 slices, then you can pull the piece of upholstery from under the plastic to access the anchor. I assume Infiniti didn't want them exposed by default for aesthetic reasons. When your done, you can simply tuck the tab back under the plastic.
