Buckmaster CTG is not the model number.. The CTG isthe abbreviation for Cartridge.Like mentioned swing the cylinder out. On the frame where the crane and frame meet will have the model number stamped in it.Value all depends on condition,finish and how it's equipted.Does it have the 3T's? (target trigger,target hammer and target grips)Nickel would bring a better price then the blued. Sounds to me you have a "K" frame probably a model 17 or 18.

Ruger Redhawk