May 1944, Army Motors:
If you see some peculiar white shapes riding around on vehicles in your vicinity—don’t shoot, they’re not enemy ski-troops. Most likely they’re the new “national symbols” authorized
by Change 10 to AR 850-5 (25 March 1944).
Vehicles assigned to tactical units anywhere and designated administrative vehicles overseas, still wear the familiar white star. But all other vehicles now sport the following national symbols instead:
ASF vehicles (except contractor operated ones at class IV installations) wear the insignia of the appropriate Service Command;
AAF vehicles flash an insignia prescribed by the Commanding General, AAF;
AGF vehicles carry a symbol specified by the Commanding General, AGF.