I couldn't find what the definition of a Checkers GM is exactly so I was wondering if it has the same requirements as chess (2500 points). Also, I was wondering if chess GMs are automatically considered checkers GMs
No. Chess grand master titles are awarded by the FIDE; see the FIDE Title Regulations effective from 1 July 2014. FIDE only awards titles in chess.
Checkers titles are awarded by the FMJD (World Draughts Federation); see the FMJD's FMJD Regulations for recognition of international titles. FMJD only awards titles in checkers/draughts.
Mikail Tal's coach, Rashid Nezhmetnidov was a checkers master as well as a chess I.M. He gave up checkers because it took too much time from his chess. It's said that he was of high G.M. caliber, but was too poor to travel and compete in enough matches to reach those norms officially. He was possibly the most creative chess master that ever lived. I think I saw this on YouTube. Google his name and "King's Walk" if you're interested.
The game of chess is much different from the game of checkers. Chess grand masters are not necessarily checkers grand masters.