You've been misinformed. Prior to the Selective Service Act of 1940, army service numbers consisted of seven digits, officially expressed in millions (0 000 000), and were assigned at random without regard to geographic location. Under provisions of the above Act, the U. S. was divided into nine regions. Eight digit service numbers - still officially expressed in millions (00 000 000) - were assigned upon reporting for active duty. Numbers were determined by several factors. The individual assigned the number you gave, 38 397 573, was a draftee, inducted in the Selective Service Region consisting of the states of Arizona, Louisiana, New Mexico, Oklahoma & Texas. The only way to determine where he actually entered service is to access records. Two-letter prefixes were added in late 1945 to reflect current status. The most common were "RA" (Regular Army), "US" (Draftee) and "ER" (Army Reserve). Service numbers had reached the sixty million series (US 60 000 000) by July 1969, at which time the army began using Social Security Numbers.