I don't think coaches know the sequence. At all. Again, not a knock on them. Most are volunteers. When the kids come in from paid programs and they have no clue, that's when I get pissed.
IMO, most don't know the sequence. Specifically, they don't understand the relationship between the lower and upper half. However, I would bet my house that most men who coach and have played baseball beyond little league, throw correctly. They do the sequence correctly themselves. They just don't know what they're doing because they do it naturally. Most boys grow up throwing baseballs, footballs and skipping rocks. They don't think about about how they throw, they just throw.
As Epstein says; "Do We Teach What We Really See?". Or, in the case of throwing, "Do Male Coaches Teach What They Really Do?".