I would agree with what Chris has said above, but with one addition.
Depending on how the company is set up and how the role of BA Manager sits within that company's reporting hierarchy, you may also want to see if/how the Perspective BA Manager has handled Senior Execs/Directors. As a BA Manager myself, I report directly into the Company's Board of Directors. So one of my biggest challenges day in, day out is to manage their expectations of why a project is being held up (or to put it another way 'why it isn't already finished'). From a BA perspective I am often asked by my team to enable a smooth pathway for them (my BAs) when they need access to said Directors.
In my experience, Directors often want a project finished yesterday, but when it comes to making time available for discussion around such things as requirements etc., they are unwilling to make the effort/find time available. It therefore, often becomes part of my role to promote my team in their efforts AND in their need to some of that Directors time.
Interestingly, I now also manage the PM side of things as well - so I guess I must be doing something right. But it helps to ensure that a Director has oversight of all project activities if they are a Stakeholder to that piece of work. So, working that aspect of their responsibilities is often useful to also obtaining their time.
So, in short, as you would ask a non-managerial BA, how he handles difficult stakeholders, ask a Managerial BA how he promotes his/her team at Senior meetings and see how/if he or she would stand up for their team. If they wont, then they probably aren't going to be experienced and will easily get shot down by other Managers.