This is still correct. Just need your itinerary to get through transit security. Then you can go to the AA gate to get your BP as they don't have a transfer desk. If you're in transit, you can go to the Main terminal and shop. BUT if you go to the other terminal by train (where your gate is), you CANNOT go back to the main terminal. That's why I recommend staying in the Main Terminal for shopping, shower, etc. until right before boarding time. The terminal were AA departs doesn't have much as far as shopping or even cultural activities to pass the time. Or many restaurants either.