A couple of observations on interviews focussed on api's -
I do not have a problem with being asked a question on specific api if I have listed it in my skill sets. I would not expect to answer an api question on struts FrontRequestProcessor just because I have MVC listed on my resume.
Usually when I have been asked such questions, it has been when interviewing with junior to mid level programmers, all of them significantly 'younger' than me.
The older folks have all transitioned into managerial function, some of them know the engineering terms obtained from reading technical publications but have not written code in a while.
Organizations with an emphasis on such questions tend to more often than not lack an "engineering culture". Emphasis is placed on delivering requirements from a backlog rather then innovating on behalf of customers and I would stay away from them.
Age is an issue, but not at the ones that matter (to me at least)