Do I need to wait to re-marry if the divorce was finalized in March 2013?

Montana law controls compliance with a decree in Montana. If Montana law resembles Oklahoma law, the decree will contain a prohibition of either party marrying again for a period of six months from the date of the decree, unless the parties remarry each other. If that provision exists, marrying within the six month period could subject you to a contempt of court situation, if anyone chose to pursue it.