Even though im 30, i still compete in the Beast of the East tournaments....which is freestyle. Hey, whatever keeps me cardiovascularly fit, its a nice motive
Freestyle= strong emphasis on leg takedowns and back exposure for points.
Greco= all upper body throws and back exposure for points.
pins are legal in both if you can get them.
I do freestyle in my offseason training to break the monotony from folkstyle wrestling. Type in a search on google and you can pull up several books offered on these two seperate styles. Good luck.