You will not earn any miles for flights on US Airways metal - doesn't matter if they are coded as American or not. "Flights operated by US Airways are not eligible for mileage accrual." -
http://www.alaskaair.com/content/mil.../american.aspx
Yes AA and US are merging but they still have separate operating certificates. Once they begin operating under a single certificate, I believe later this year, many of us are hoping those pmUS flights will become eligible for mileage accrual.