Its been over for a long time. This changes nothing. Even if you could, who would be stupid enough to open a MMJ store in Montana. It like putting a sign on your back that says "Hey come send me to prison".
Land is cheap in eastern MT, but that side of the state is flat/ugly/rural and good pot is scarce.
The western side of the state is gorgeous and flooded with super dank. But land is hella expensive.