The regiment has a long history that precedes its association with the division by almost ninety years. Constituted and organized as a component of the New York State Militia 23 October 1850, the regiment has won battle honors in the Civil War (eleven streamers), Spanish-American War (two streamers), World War I (five streamers) and World War II (five streamers). Elements have been awarded two Presidential Unit Citations and a Meritorious Unit Commendation. Regiment was assigned to 44th Infantry Division from September 1940 to July 1946, during which period Company M was the heavy weapons company of the regiment's 3d Battalion.
Indications are your information comes from Rader's discharge. If so, this means only that M/3/71 is the unit he was assigned to at the time he was processed out of service. He may not have served with the company, regiment or even the division overseas.
Clarence Anspake is president of the regimental veterans association. He may be able to assist in establishing Rader's dates of service with the regiment:
2015 Newbridge Road Bellmore, New York 11710-2203 (516)785-2593
13026 Lefferts Boulevard South Ozone Park, New York 11420-2706 (718)843-1210
Records generated during the regiment's active Federal service are in custody of the Fed but the New York AGO may still have some sort of record of his service. You decide whether it's worth a try:
Adjutant General 330 Old Niskayuna Road Latham, New York 12110-2224