The FDA does regulate tobacco these days and while they might require an ingredients list at some point, I doubt it will break down the tobacco by specific leaves/curing techniques. It would he similar to what is required in certain European countries where they will list tobacco, water, any humectants or flavorings, etc. That is actually kind of useful for figuring out if and what added flavorings are used but not much help for leaf components.
I know FDA regulates how the ingredients are listed by order of their amount in packaged food. But I don't think FDA regulates tobacco. And whoever does, ATF?, it doesn't seem to have a similar guidelines.