It is very unlikely that a dealer will ever offer the full Kelley Blue Book trade in value price. Kelley Blue Book prices tend to be a bit overinflated and a dealer needs to be able to make money on the vehicle when they resell it. The majority of trade-ins will come in well below Kelley Blue Book value. There are a few circumstances where a dealer would offer close to the KBB value. If the car was a very popular model or in short supply, a dealer would offer a better trade in price. Kelley Blue Book does give you a general idea of what you can expect for your vehicle on the private market, and can be used as a good starting point for negotiations.
For more info, see Figuring Out Your Used Car Trade In Value