Here's a photo of my 40 panel I owned a while back. Notice the headlights and grill......I think the headlights were in this position for 39 and 40. In 41-47 they evolved onto the tops of the fenders.
http://smg.photobucket.com/user/olddodges1/media/40 Panel half ton/MVC-001S.jpg.html?sort=3&o=7
I think the dash changed in 41 too and did not have the vertical strips in the center of the dash like my 40 did.
http://smg.photobucket.com/user/olddodges1/media/40 Panel half ton/MVC-005S.jpg.html?sort=3&o=3