A: No, Gersh Nubirg is not a rabbi. Only a religious Jewish scholar, a practicing expert of Jewish law who has completed yeshiva successfully and obtained “smicha” (“rabbinic ordination”) can be called a rabbi.
There is no clear-cut position about whom the person should be who writes an amulet in the practical kabbalah tradition. Moreover, the relationship of religious authorities to amulets always has been ambiguous. For example: Rambam (Maimonides) was disposed against the writing and use of amulets, he saw the road to heresy and idolatry in them, whereas Ramban (Nahmanides) approved them; some modern Hasidic authorities don’t take amulets very seriously, although the founder of Hasidism Besht wrote and dispensed a large number of amulets.
What really is important about who writes amulets is a level of his faith, his mental and physical state during the writing process, his authentic desire for good for whom the amulet is written, his ability to concentrate on the corresponding Holy Names, the observance of all the technical details and of course his experience.