An update
The Academy model as mentioned had some significant (for a clarinet) differences between the Academy and the regular Pro model.
# 1 - Tonehole diameter. Here the Academy model had smaller toneholes - nearly all of them from top to bottom compared to the Regular Pro model. Here are some sample measurements from the upper joint.
. . . . . . Pro model . . Academy Model
KEY . . . diameter . . . . . diameter
1st trill . . 4.69 (all in mm) . . 4.42
2nd trill . . 5.48 . . . . . . . . . 4.76
3rd trill . . 4.55 . . . . . . . . 4.64
4th (Bb) . 5.9 . . . . . . . . . 5.26
throat A . 5.08 . . . . . . . . . 4.46
Throat Ab . 5.05 . . . . . . . 4.55
# 2 - register vent. Not only was the Academy register vent LOWER on the body but it also was Larger than the regular Pro model.
# 3 - Bore - the bore on the Academy Model was larger than the regular Pro model. (keep in mind, bore diameter does slightly vary from instrument to instrument, but I have not analyzed this to see if it is a non-round issues versus a real variance excluding the other problem of it being wood which varies with temperature and care and manufacturing).
Why is this significant. There are a couple different "versions" of Academy models. This one is significant because we also happen to have a regular Pro model only 245 builds away, which for all practical purposes unless we get a closer "set" in some time is it's virtual manufactured twin.
The larger bore, after an internal analysis seems to be the same bore shape but just further down the instrument. Which, just guessing, we'll guess that it was bored too deeply. And we can also guess that the bore was cut before the tonehole holes were cut, and before the register hole was cut.
To accommodate the increased volume bore to keep the playing resistance similar they cut smaller tonehole diameters.
Also to accommodate the smaller tonehole diameters especially for the throat key they adjusted the location and diameter of the register vent.
So was the Academy Model a "mistake" or a 2nd line. Since the Academy model seems to be somewhat infrequent I would guess it was a manufacturing mistake, at least this particular vintage Academy Model.
In short, the Academy model is a fantastic playing clarinet. It is comparatively a slightly more tonally centered sounding while A/B'ing them which makes sense due to the tonehole diameter. But few players would even know that or even be able to compare it. The Buffet though is a Buffet and it is a wonderful playing instrument. We just have debunked one version of the Academy Model.
On another note,
One of the largest differences between a Pro, Intermediate and beginner clarinet for the player is tonehole diameter. The smaller the toneholes the easier it is for young players fingers to cover the holes. In the past student instruments had smaller diameter toneholes than intermediate, which was smaller than Professional models. Of course, there are other differences in keywork and other items.