This is spot on.
He was not what is known as a method actor. In method acting, the actor, relaxes and becomes a kind of blank slate that can experience the emotions of the character they are playing. It's a process, for sure. Wierwille, on the other hand, was more of what would be known as an action based actor. In action based acting, if you want to appear happy, you smile. If you want to appear sad, you frown, and so on. You don't need to actually experience the emotions you are projecting. Wierwille was very good at this and fully aware of what he was doing, without actually experiencing the emotions he was portraying. That's what con artists do. They can't afford the luxury of experiencing the emotions of their marks.