I was about to book a flight on Cathay Pacific in Economy - S but it was mentioned that I will not be able to pre-select my seat. I called customer service and they told me that while I cannot choose my seat at booking I can choose my seat upon checkin 48 hrs before departure.

It's low season, route is BLR-LAX 3rd week of October, what are my chances of finding a window or aisle seat? It's $150 more for the next fare class up that allows the option of pre-selecting my seat.