If I recall correctly, Montana uses a reasonable person standard in determining whether the weapon is concealed or not. Ill try and find the a case that I think I am recalling that from. However, I don't recall any case law that specifically calls out the use of IWB holster.
Of note, I have also heard several times of an email to the AG office asking clarification if an IWB Open Carry would be considered partially concealed or openly carried and the reply was that it would be considered openly carried and not concealed. However, I personally have not seen this email to confirm its contents.
While its not directly related, Its also good to remember that conceal carry laws are only relevant while within the boarders of an incorporated city. See MCA 45-8-317 for conceal carry exceptions, specifically (i).
Originally Posted by MCA 45-8-317