There is however another ARCOM. Which is the right I do not know.
From Wikipedia:
The Army Commendation Medal is awarded to American and foreign military personnel in the grade of O-6 (Colonel in the U.S. Army) and below who have performed noteworthy service in any capacity with the United States Army. Qualifying service for the award of the medal can be for distinctive meritorious achievement and service, acts of courage involving no voluntary risk of life, or sustained meritorious performance of duty. Approval of the award must be made by an officer in the grade of Colonel (O-6) or higher.
The medallion of the Army Commendation Medal is a bronze hexagon, 1 3⁄8 inches wide. On the medallion is an American bald eagle with wings spread horizontally, grasping in its talons three crossed arrows. On its breast is a shield paly of thirteen pieces and a chief. The reverse bears a panel for naming between the words FOR MILITARY above and MERIT below, all placed above a laurel sprig. The ribbon is 1 3⁄8 inches wide primarily of myrtle green. It is edged in white and in the center are five thin white stripes spaced equally apart
