I've found that it depends on whether or not the individual airline prompts you with a seat selection map when you try to make a reservation on their website. Just remember that this info is sometimes not all that accurate for nonrev seat availability as some airlines (eg Delta) sell tickets without a seat assignment. (HK or HK1 designation)
Often a call to reservations explaining that you're an OAL Standby SA or ZED fare passenger will get you the load info if the res agent happens to be in a good mood.
I try to call them during off peak hours when they're not busy.
Last edited by wanabee777; 9th November 2015 at 19:32.