If past history is any indicator, an aircraft order will follow a new pilot contract. That's what happened with the 777/737 order in 1997, and new aircraft are the only carrot AA has to offer right now.
Also, remember what happened with DL when they ordered and took delivery of their B777's... There wasn't any language in their pilot contract regarding pay rates or duty time for long haul flights, which put DL in the position of negotiating a less than optimal agreement because the aircraft they were taking delivery of were essentially grounded...
Having said that, AA just recently resolved the issue of long-haul flights outside the normal contract negotiating process, so it's possible that there could be an order before negotiating a new contract. I just don't think it's very likely to occur.