Yep - the devil is in the details. DS' GT Pre-Algebra course actually had a unit on trigonometry and many units on Geometry. They have finally renamed the course "Transistion Math," which makes a lot more sense than Pre-Algebra. In my day, we had a separate trigonometry textbook that was covered in full all at once the same year as the Geometry textbook. I think that was why the Pre-Calculus course couldn't be stretched beyond the one semester and they crammed AP Calculus AB into the second semester of that same year.
I agree that the textbook makes a huge difference. Traditionally, the GT classes use different textbooks and they don't seem to change as much (LOL - I guess no one wants to spend money on them).
My concern is that they are stretching the material to fit the audience because they also try to be more inclusive with the GT and Honors labels as they go up in grade.
By the way, I think there is a distinction between the courses and the exams. If you completed the AP Calculus BC course, then you have the option (depending on your confidence, etc.) of taking the AP Calculus AB exam or the AP Calculus BC exam. If you have only completed the AP Calculus AB course, then you would take the AP Calculus AB exam. In our districts, you cannot sign up for the AP Calculus BC course without passing the AP Calculus AB course since the former picks up where the later left off.
