Hello, I'm just under 24 hours from STL-DFW-SYD, which I booked on Qantas, with the STL-DFW leg on AA, so it's my understanding I need to check in with AA since they operate the first flight. No problem, I have my AA record locator.

I tried to check in on AA.com and it says I need to check in at the airport, which I think is fine because they need to see my passport. No big deal. Of slight concern is that for QF7, AA says my seat is unassigned (same for my return flights). However, I paid for a seat selection on qantas.com several months ago. I'm worried that since AA isn't aware of my seat selection, when I check in at the airport, that selection might somehow get lost and I'd get stuck in a middle seat for 17 hours. I've been burned before with losing seat selections at check in on other airlines and don't want it to happen here, especially on such a long flight.

Do I have anything to worry about? Will AA even give me a boarding pass for QF7 or do I need to pick it up from the Qantas desk in DFW? Thanks in advance.