I think lounge access for QR flights depends on the booking class; IIRC the cheapest types of business class tickets do NOT include lounge access.
The fact that the ticket is bought as AA8134 also means that if you choose to accrue frequent flyer miles in the AAdvantage program, you will earn as if you were on an AA flight and miles/Loyalty Points will be based on the price of the ticket, not the distance flown.