Plague stuff was about 4-5 years ago, unmolested places should be good again.
Rosebud requires no lead bullets last I heard. They do a piss poor job keeping up their website.
Their guide requirement is real, and even though the guides want to leave you by yourself, don't let them. It's a ticket for the hunter, not the guide. they have a guide list, and you should get references before arranging a guide.
Melette county to the north is riddled with Indian controlled lands too, by lease or by ceded deed. You need a plat map to check ownership.
HM