The only thing that pops out to me is where you are measuring your torque tube length. If you consider the rest of the tube "bell" that is inside the pivot housing as part of the overall length of your tube, my eyeball measurement from your pictures would put that at the 60-5/16" length listed for the 1948-50 tube.
Your existing cross rear frame width could be just slightly skewed wide based on normal age and wear-tear expected to be found on a truck of this vintage. It could very well be either a 1947 or a 1948 frame as only a minor tweak could cause the frame to spread to that dimension.
On another possible tangent to ID'ing your chassis, see if you can locate and post the serial number from the rear axle. Should be a 2 letter + 4 or more numeral stamping that we can use to check for what year truck it belongs to.
