I go to mercer and I've never heard of Mercer notes. However, I should mention that several years ago a student made and published notes about each of the phases here (we learn use an organ system approach, rather than discipline-based).
I too am a Mercer student and the only other time I've heard of "Mercer notes" was from an MCG student asking about them. From what I can gather, they are either a myth or are so underground that even I don't know of them.