the stamped frame numbers never included the first letter, which is what designates the weight class and frame length .... the 3200 is a long bed 1/2T, which as Tim mentions would have an M as the first character on the missing vin tag, a 3100 short bed would have started with H, a '55 long 3/4T would have a G ..... in '56 they changed it all again
Bill
