If you're an AS elite, which I assume since you said you fly AS a lot, and there are only 2 seats available, that's a good sign that it's a VERY full (if not almost oversold flight) since elites are able to pick from any seat on the aircraft. If you're not elite, most if not all of the first half of the Y section will be blocked out so your choice of seats is more limited and in that case the elite section could be empty, but the non-elite section full (and therefore it isn't necessarily a "full" flight).