If you're catching Blaine County on that TG, which looks likely from the radio ID, I would imagine it's simply the SO dispatch. Montana counties do have coroners, but they are generally just the Sheriff and sometimes a select couple deputies, unlikely to be a separate channel. The nice thing about Montana is that most counties, at least for SO, use the county number in badge numbers, so grabbing a 24-XX callsign essentially confirms the location. Butte, of course is different, because Butte.TG - 02321 Blaine County, possibly coroner.
Radio IDs 2490011, 2412007