No the coaching for GRE is not sufficient for GATE preparation.

GATE exam is the ticket to get admission in M.Tech in Indian universities and its score is accepted in countries like Singapore and Germany. Students can pursue even M.E, M.S and PhD after clearing the GATE exam. Through GATE students get scholarship support and the opportunity to study in the top engineering colleges of the world.

GRE gives importance to the English language skills of the candidate besides gauging them on other subjects. The GRE score is accepted mainly in the U.S. After acing the exam, students can go for M.S and PhD.

The syllabus and aim is not exactly the same.

It is advisable to focus on just one and do not depend on one for preparation for other exam. It will not help you any how.

Good Luck!!