Aren't they also on the OKWIN system as well?
Not that I am aware of. Last time I spoke with those who use the Lighthorse repeater, they wasn't going to go to OKWIN as it didn't provide coverage to the entirety of the Muskogee Creek Nation tribal jurisdiction. Mainly anything south of Okmulgee where OKWIN coverage is non-existent. (Hughes, McIntosh, & Okfuskee counties.)
Plus they where floored by the price that the state wanted to charge them to have talkgroups on the system.
Last time I heard, they was looking at putting in their own DMR multi site trunked system to cover their jurisdiction which would include their casinos. But that was about three years ago and it doesn't look like that has occurred.