Its in the Mission Mountains. Get a Montana Gazeteer and find Finley Canyon. And don't EVER EVER EVER EVER call REI for any beta on anything. Also, I don't think there is a UM Climbing Club, at least not while I was there. I mean why do you have to be in some gay ass club to go climbing?
I would try Trailhead or Pipestone Mtneering, but its hit or miss you might get some knowledgeable person, or maybe not.
Unfortunately, I never climbed in Finley when I lived in Missoula or I'd tell you myself. I could make some calls and find out but since I don't know you I won't. Good luck.