If the person you met in bozeman who is into boykins is who I think it is, I would bet that he is talking about the Bodoin refuge up by Malta.
It is a long drive from Bozeman, but understand that it is good before it freezes. For late hunting, around x-mas, check out the Bighorn near Hardin. It is a tailwater, and never freezes. When the Yellowstone locks up, it rules.
Also, there are a number of spring creeks north of Belgrade and Bozeman along the east-gallatin that are truly amazing if you can get access. But from what I hear, the friendly farmers who will let you on with a knock on the door are pretty much gone...
The late hunting in MT is awesome if you can find open water.... Still plenty of ducks early, but they are more spread out. Good luck, boykins are the best.