If you are coming to Montana the state recognizes Concealed Weapons Permits from most states. Having a concealed weapon in a bag, briefcase, purse, and ETC is probably going to be considered a concealed weapon by most LEO's if you are in an incident or stopped by police and will probably require a Lawyer to get the situation resolved. Who knows, it might be the incident which clarifies this issue in Montana Codes Annotated, remember most Montana Gun Laws date from the1880's, thus the mining or logging camp exclusions to permit-less carry in the state. My best advice is to get a permit from your home state or a non resident permit recognized by Montana.
Bob, Western Montana