Ok, I know this thread is old, but I've been taught to search before posting. So I did. I too, have an '04 Grand Am (4 door if that matters) and I've read the vehicle manual to see if I can install with LATCH in the center, but it shows the two outboard spots as LATCH locations (I guess you'd put it that way). When you said to refer to the car seat manual, how do you know if its allowed in the center? I'm just a little confused. And why is it up to the car seat whether or not you can install in there. Its up to the car, not the car seat, when installing it to protect your child.
My manual says specifically, word for word...
Your vehicle has the LATCH system. You will find anchors (A) in the rear outside seat positions.
This system, designed to make installation of child restraints easier, does not use the vehicles safety belts. Instead, it uses the vehicle anchors (A, B) and child restraints attachments to secure the restraints. Some restraints also use another vehicle anchor to secure a top tether strap (C). In order to use the LATCH system in your vehicle, you need a child restraint designed for that system.
So can I LATCH in the center, or not? I'm confused about the whole having to check your car seat manual thing.