I think that FWP (Fish Wildlife & Parks)sells hatchery raised trout to other states and the feds.. maybe the tribes too.. but I could be mixing up the fed hatcheries with the states
FWP owns or operates ten hatcheries annually stock approximately 50 million fish annually into approximately 836 lakes and reservoirs and approximately 23 rivers or streams throughout Montana. FWP’s hatcheries provide eggs and fish to support both sport fisheries and native fish restoration programs in Montana and neighboring states.
Montana Fish, Wildlife & Parks :: Hatcheries
And the Feds have hatcheries here too:
Welcome - Ennis National Fish Hatchery: U.S. Fish and Wildlife Service
Last time I was there (3 or 5 years?), they had a display raceway of Albino, Blue and Orange rainbow trout - really cool