I think it's important, if you're going back to the section 87 exemption, that this applies and clearly is delineated as applying on the reserve lands. In the case of indigenous governments that are post-treaty, it would be the reserve lands at the date of the signing of the treaty, so just prior to entering into treaty.
That section 87 exemption obviously carries with it an exemption from tax, but groups can choose to tax there. Post-treaty, what you're talking about, is the settlement lands, which can be much broader than the reserve lands prior to treaty. You're not bound by those lands when you're opting into a tax framework.
Yes, there are different treatments that flow out of whether it was designated as reserve land or not.