What type of weapon? What type of terrain? Will you be equipped and able to pack in a few miles? Lots of questions.
MT takes a while to learn as far as regs go. Basically, you get a combo tag. Then you have to look at all the different units and see if it has a general season or limited quota season. Then look at the dates that the season is open.
As far as grizzlies go, if you hunt in northwest Wyoming or southwest Montana, there will be grizzlies. Bugle magazine just had an EXCELLENT article about defending against a grizzly. Basically, looking back at past grizzly encounters, it said that bear spray is the most effective thing to have. If you have a gun, you probably have to hit it on the brain to stop it if it was charging. That would be a helluva touch shot, even at close range.