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.