Model 19 is also known as the "combat magnum". Your revolver is the fifth variation of that model. The -5 was the change from the pinned barrel and recessed chambers on the cylinder. The P&R revolvers are preferred by S&W collectors as are the shorter barrel guns. Nickel guns were produced in much less volume than the blue guns and therefore bring a slight premium over the blue ones. Six inch guns are considered excellent for shooters due to the longer sight radius. Placing an accurate value on an unseen gun is impossible. It's like asking how much is a car worth.