My 42 Chevy Fleetmaster has a brass plaque attached to the dash on the left side just under the gauges. It has an A 824 H engraved on it. The previous owner thought the car may have been used by the military or some other government agency during WW2. The previous owner recovered the car from barn storage in 1976, had it painted in 1980 and the rest of the car is all original. I have not been able to find any references to explain the dash plaque.