All glued up.
While I love exposed dovetails they have their place and I don't think this case is it . Miter joints are the weakest joints and need reinforcement,usually a hidden spline or exposed cross spline or"fake" dovetail. Since this piece is for himself no need to expose the skill for others to appreciate. Ol' Sasquatch can throw this case around without worrying that it will fall apart.I'm always intrigued by the purpose of hidden dovetail joints.
While I appreciate the craftsmanship, it sure does seem like a lot of extra work for what looks like a mundane miter joint.