Indeed, this is the same person. The entry for "David ben Solomon ibn Zimra (Radbaz)" in The Responsa Literature states:
He conducted a large yeshiba and many famous scholars were his pupils. The great talmudic author, Bezalel Ashkenazi, was one of them; and Isaac Luria, the world-famous kabbalist, was another.
As for your impression about devoting his ...
A similar concept is used today, in which a variety of symbols are used from various Rabbinical organizations to mark kosher food (bread included). Read more about hechsherim (singular: hechsher) here.