I asked Kimber if my hunter could be fitted to a Montana stock and they said no. Whether that means they just won't do it or it isn't compatible I don't know..would be interesting to know
You'll need the following parts to convert a Hunter barreled action into a Montana without muzzle threads.
Stock with trigger guard and sling swivel studs
Magazine well
Magazine follower
Magazine spring
Front and rear action screws
Procuring the stock is the hard part, and given the cost you're better off just buying a Montana.