If build 14308 is the BUILD build, I suspect the next insider build might actually be later. They are up to 14311 now, with 14309 and 14310 after 14308. Yes I realise people can count, I'm just referring to that they haven't skipped build numbers. A separate guess, these later builds may simply be last minute bug builds for BUILD, seeing as they have been daily and the last one 2 days ago.
To see if we can get it working. The Insider Build will be 14306, 14308, maybe 14310 but what ever it is we will need a new esd-decripter to convert .ESD to .ISO and hopefully Abbodi1406 can update his from this build.
There will never be a "final" Windows 10 build". Are you asking if 14308 is the "official" Build 2016 release? And does it really even matter if it is? A new Insiders Preview version will come shortly after it anyway.
The BUILD build (lol) will just be another Insider Preview, the "Final" RS1 (Redstone 1) build is planned for July.