It is both, at least that is how it has been explained to me. The two components of Cajun Standard tuning are:
1) Use of the "just" tempered scale intervals.
2) Relatively dry tuned (~5 cents sharp) on the second set of middle reeds.
I am sure that different builders have different opinions on this subject, but this is what I have been told by several of them. They don't all use the same terminology, but that is what it boils down to.