Nope, as most, if not all, teachers are volunteers, they do not
know much about Wesley's theology.
The ideal is to have all teachers theologically trained. The
reality is, as long as they are not too spiritually immature, and
willing, they will be roped in as teachers. Most SS follow a fixed
syllabus and come with teacher's guide. As long as there is little
deviation, then it is considered safe.