This is a F-5W, not the F-5E. ESP LTD have yet made a production run of the F-5 in walnut. 

This is a sample/preproduction guitar. ESP makes the samples to test out various colors, finishes and to show to dealers prior to the actual model being
built. They take them to shows like NAMM and start taking preorders for the new years model. Some Samples are never make it into production models.