This is pretty sweet, it has extra pins in it and a free case. The case is a bit older and a bit dusty on the outside and a little beat up but not bad. This is an older Gus-600NT and was apparently used in a photo shoot. I am not sure if it was for the ESP website or a magazine or maybe even with Gus himself. The guitar is not signed or anything fancy like that but just looks good and with those Duncans ill bet she screams too! 

The specs from the 2009 ESP website are:

• Set-Thru
• 25.5” Scale
• Alder Body
• Flamed Maple Top
• Maple Neck
• Rosewood Fingerboard
• 42mm Standard Nut
• Thin U Neck Contour
• 22 XJ Frets
• Black Nickel Hardware
• ESP Locking Tuners
• Tonepros Locking TOM & Tail
• Seymour Duncan Distortion (B) / 
  ’59 (N) p.u. w/ Coil Split Mini Switch
• Finish: STBC

As this is a Sample/Prototype guitar some of the specs might be a bit different from the production model. We can see the extra strap pins are not on the production models. 

It 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 made into production models.