Originally Posted by
lalalandMCI
The few times I have been booked onto AA I was always booked into Y, and when DL booked me onto UA it was in Y, and I got the bonus.
+1
A rebooking at the end of 2013 on UA > AA put me into full Y. Not guaranteed, but it seems to happen more often than not.
@OP: Don't forget to claim the miles for the AA flight, if you've not already done so.