Volume 13-14 is out already (covering Japanese book 6, and featuring the Jagd Mirage for the first time.)
As for the Knight of Gold, you're incorrect. There's 4 Knight of Gold's, the first being the Auge (Amaterasu's first prototype), the 2nd being Schpeltor, then the 3rd and 4th being the previously shown KOG and KOG AT (Paratisque Mirage).
The V3 is simply the V3, as in the 3rd rendition of the KOG. Nagano frequently redesigns his Mortar Hedds, the LED and KOG V3's being the newest of the bunch.