Are any of the 2pt shots actually off the JS skill or are they all inside shots?
If they are inside shots, is it worth training JS and JR to improve the % of those few shots?
Kozlodoev answered this, but I'll try to expand on it from my observations.
You can tell what kind of shot a 2pt attempt is in two ways. The first is via the commentary, which will often be pretty clear (eg 'baseline jumper' versus 'lay-up' and so on). The second method is by observing where on the court the shot is taken.
If the shot is taken outside of the paint (or the lane, or key, call it what you will) it will be using JS (IMO) to determine success. Inside that demarcated area, then it will most likely use IS.