Forensic analysis of a bullet removed from a corpse can tell you the bullet caliber (in this case .38 special), assuming it is not too fragmented or misshapen. It will not tell you the exact make, model, and manufacturing year ("Smith and Wesson Model 10 made in the 1920s") of the gun from which it was fired.
That would be akin to telling the make, model, and year of a car from looking at a tire track in the mud.
