What is the red book value of a 1988 GMC truck?

The red book value is used to tell you an estimate of the vehicle you own is worth or other items for that matter. In order to find out the value of your 1988 GMC truck, more information would be needed. For example, what is the condition of the inside and outside of the truck? How many miles are on the truck? What truck do you have specifically, is it a pick up truck or SUV? These things can change the appraisal amount of your vehicle.