While the references in the BLU questline and Bozja is a pretty big tease, it still isn't a sure thing. You could try to read into it, but like that whole Necromancer/Chemist/Beserker discussion a few weeks back you can only make predictions until you get confirmation. It helps that unlike those class archetypes mentioned, BST has been directly and repeatedly name dropped with actual characters being referred to as such. Besides CHM being given a wink in one short interaction, there hasn't been that many jobs for legitimate consideration.