[dwcsr]

Here's why its a 47 or 48. I enhanced the picture a bit.
The top white arrow should have a vertical brace to the floor here on a 49 and later side mount cabs. Arrow 2 you see the vertical brace that has a wrapped around apron to the door only on 47 and 48. This is hard to see if your not familiar with 47 49 roof panels, but the red arrow shows the roof tapers to the windshield pinch weld (47 - 48 only) not a stepped down as on 49 and later. The two other pictures are the inside of a 47-48 cab and the differences in the windshield pinch weld area, left 47-48 right 49 or 50