I'm only speculating here but it is possible that the ADA3700CFBOX designation corresponds to the ADA3700KA5CF (tray) part as a PIB part number. The KA5CF has the new E6 stepping. A quick inquiry to Newegg would probably solve the mystery of the new CFBOX cpu. UPDATE
Well, Newegg was no help but I just noticed something - look at the last 2 letters of the new ADA3700FA5CF and then look at the number Newegg lists: ADA3700CFBOX. I was just over on AMD's website again when I noticed this. I would say this is a new s939 A64 3700+ cpu with an E6 stepping. Good eye ZenPirate.