I have not seen where the game rating might be. You know the E (Everyone) T (Teen) M (Mature) type ratings.
Thanks for the help

I don't see any either, but that may be simply because different countries use different rating systems with different criteria. Plus, while none of the games yet predate the ESRB there is no guarantee that there aren't any GOG-worthy games before 1994.
Furthermore, just because the ESRB was established in 1994 doesn't mean that everyone was already on the bandwagon. Stonekeep, released in 1995, isn't known to have any official ratings as far as I know.
If Good Old Games really wants to service those who may have issues with content I'd recommend either having their staff play the games themselves or have a user-based system that would list "potentially offensive content" on the game's main page. Slapping "Mature" and "Teenager" on games is simply too vague and presumptive of moral standards, in my opinion.