The Stargazer-class is a Heavy Cruiser in-game. However, if you're refering to the U.S.S. Stargazer that Picard was captain of before the Enterprise-D then no, it's not in-game as that ship was a Constellation-class ship.
The closest approximation is probably the Cheyenne Class. It's not the same, but is probably the closest you can come to it in game. All classes of cruiser at this level (except the Excelsior) appear to be based off of the Constellation class that the Stargazer belonged to.