Over six hundred (600) field artillery battalions, designated 1st through 1125th, were active during the war. Most of these served overseas in either the European or Pacific Theaters. Not a simple matter of "grab a unit and run with it".
Re 494th Armored Field Artillery Battalion. The 494th was only one of three allotted to 12th Armored Division (the others were the 493d & 495th). The 12th was only one of 14 armored divisions active during the war, all of which served in the European Theater and each of which was allotted three 3 armored field artillery battalions; a total of 42 divisional armored field artillery battalions alone.