The fin is shaped a lot like the Great Planes PT-40 & PT-60, and possibly every other trainer out there.
What did the owner say it is?
What is the wing span?
I've never seen an ARF trainer in those colors. Did he say it is kit built? Or is it an ARF that has been re-covered?
What engine does it have?
What receiver and servos?

None of this really matters though. Unless it's a pile of dog poop it's worth 75 bucks. If it's built well and straight, one trainer is about like the rest.