He still has them made at GM. It's a thicker-edged version of the Mana which he has been using since the beginning of 2015. Since then the shape hasn't changed. Previous to this his bats were a similarly chunkier version of the Six6 (personally I prefer this profile. In fact so much so that I actually own one of his bats from 2014).
New Balance retail bats are made by Sareen. Millichamp and Hall as far as I know have absolutely nothing to do with new balance. A cursory inspection of one of their bats would clear this up as they are vastly different in many ways.