Nope.
The worst is when I read on websites from instructors that they advertise themselves as "master scuba diver instructors". What the heck does that mean?
R..
I'm not sure about "Master Scuba Diver Instructors", but since you are discussing the PADI Master Scuba Diver rating, I assume you mean the MSDT (Master Scuba Diver Trainer) rating for PADI instructors.
Once you become a PADI OWSI (open water scuba instructor), the next step is to become qualified to teach one or more of the PADI specialty courses. Once you have a minimum number of certifications under your belt, and are qualified to teach at least 5 specialties you become an MSDT. It is simply a designation that says you are qualified to teach a student all the necessary components to achieve the Master Scuba Diver rating. The MSDT rating is also a prerequisite to moving on up the PADI instructor ladder.
Hope that helps clarify your question.