Boeing or Airbus time won't mean squat.
The training department will need to go to training on the Airbus, and develop a syllabus that the FAA approves. Once this is accomplished all pilots that bid and are awarded the Airbus will have to go through the entire training syllabus. Having (or not having) airbus time will make no difference.
I can't understand why any of you would think that it makes a difference in the seniority based 121 world. I understand startups like VA that operate only one type weighing more heavily on Airbus typed individuals, but a global airline like AA, with multiple types of aircraft, could care less.