Rich,
According to my January 1952 ORER, these are most likely GN series 38500-38599 and 38600-38699 all steel auto boxcars with Type E Evans loaders. Later in life, these cars were likely used for lumber and plywood loading.
The 3200 series numbering of the various GN scheme cars from Accurail is puzzling, as cars in series 3000-7999 were steel underframe, 5'-5" wide door cars, according to the same ORER. (The ORERs give the door opening width, not the door width, which wold be greater.)
Todd Sullivan