It actually happens quite often. There is usually at least some staff changes due to various reasons. Insurance minimus changing as aircraft change and sometimes an owner isn't happy with the current crew and the aircraft change provides an easy out to get ride of any unwanted pilots. It sucks but it happens. Very rarely is it the whole flight department replaced but it has been known to happen.

However, that wasn't the point of what I said. The point was know some basics about the aircraft you are about to apply/interview for or don't expect to get the job.