do any dealers go by nada,black book or kelly blue book prices

they are correct that they are just guides- the book typically doesn't take off enough for high mileage or add enough for low mileage, and they can also be several months behind what is going on at the auction. If you are looking at a high demand car, don't be suprised if it is at or above book value- at that point you have to decide how bad you really want it. GMC Terrains have not had any rebates from the manufacturer since they came out in 2010 (GM can't build them fast enough to keep up with demand), so they are an example of a vehicle that is holding high value (32mpg on the highway, safe suv).