Already many within the project management world are distinguishing between Agile PMs and Traditional PMs. But does this mean that the growth of new methodologies will lead to PM specializations?
I guess it depends on how you look at things. Right now, the answer is maybe. I think it is safe to say that we are not there yet, but is is possible? Sure.
As new methods come out, though, it will not be necessary to create specializations for every single one of them. It will be interesting as things evolve in PM to see what comes of the new methods, but I think the more important goal for current PMs is being able to use and successfully implement these new methods as opposed to worrying over the right label.