I booked two award tickets VIE-MAD-DFW in August using American Advantage miles with the first leg on IB and the second on AA. Using the AA confirmation code I can select seats on the AA flight. Using the IB confirmation code the IB website and app offer seating starting at $16 per seat. But the IB website says:

”Customers with tickets purchased with Avios (or equivalent in miles) in Economy or Blue fares may select a seat free of charge when making their booking.”

Will I have to pay for advance seat selection on this flight? I am One World Ruby if it matters.