D Series - What Year/Model?

A few years back I snapped this picture of a beautiful D Series in a parade. Thought I'd share the pic. Can anyone tell me what year and model it is?

With out a serial number the exact year is not possible. Based on the photo it could be anything from 37-40. As for model. Don't know other than its bigger than a d2 or d15 likely bigger than a d30

Its a D30 or DS30, you can tell by the wheels, short length of the hood and the front fenders don't have a bead rolled in the edge.

Whatever it's credentials, it's a nice looking truck! Someone's brought back a classic and it's really nice.