Was The 3rd / 7th Army only during WWII?

The I Armored Corps was redesignated the Seventh Army on 10 July 1943 while at sea en route to the Allied invasion of Sicily as the spearhead of Operation Husky.
The Seventh Army was inactivated in March 1946, in Germany, reactivated for a short time at Atlanta, Georgia, then inactivated again. It was reactivated by the United States European Command (EUCOM) with headquarters at Patch Barracks, Stuttgart-Vaihingen, Germany, on 24 November 1950 and assigned the command and ground service forces of United States Army Europe (USAREUR).
In 1959, Grafenwoehr becomes headquarters of the Seventh Army Training Center, incorporating the Grafenwoehr and Hohenfels Training Areas to become the largest training complex in Germany. In 1975, Grafenwoehr becomes the headquarters for the Seventh U.S. Army Training Center, which becomes the Seventh Army Training Command the following year. As of January 2006, the 7th ATC became known as the 7th Army Joint Multinational Training Command. In July 2016, the 7th Army Joint Multinational Training Command was returned to its original designation as the 7th Army Training Command.

JMRC/JMTC/JMSC (Grafenwöhr and Hohenfels) are 7th ATC

3rd Army was the Army of Occupation in Germany after WWI. The patch reflects with the white "A" and the red "O". The blue completes our national colors.
In the picture, I'm a 2LT with the 3rd Army patch at Fort Benning at 1965.
AT that time, 3rd Army and other army HQ's in the US were known as Continental Armys, or CONARCS, commanding certain areas of the country. 3rd Army had the southeastern portion of the US and was based at Fort McPherson, GA.
It was active 1918-1919, 1932-1974. and reactivated in 1982 to be the Army component of USCENTCOM.
As a result of the 2011 BRAC, it moved from Fort McPherson to Shaw AFB, SC.