Print Regulations:
Administrative Rules of Montana: Current edition may be held at State Law Library of Montana. Georgetown Law Student may request scans via Interlibrary Loan.
In Westlaw, see also historical regulations, currently proposed & adopted regulations, and regulation tracking which can be found on the state's Regulations page.
State registers and regulation tracking are offered by Lexis, found on its Administrative Codes & Regulations.
In Bloomberg Law, proposed, final, emergency, temporary, and interim rules, plus regulatory notices can be found under Rulemaking within the State Laws & Regulation collection.