The oldest Dodge truck I've dealt with was a 39, and I don't know how much stuff interchanges between those years, but the 39 cab was what was used for all Dodge military trucks up to the 1968 model year. That means there are a lot of parts available for the 39-47 cabs. www.vintagepowerwagons.com could be your best friend They have a lot of parts remanufactured to original specs.

Those parts include locking door handles. The keys fit into the handle itself and you can then lock both sides. Unfortunately, you have to lock each door from the outside each time, I got a set for my 39 and was able to get a pair with matching key locks. That options seems to be more available just after a fresh batch is run, so its kind of hit or miss on the matching locks. Another point about the locking handles is that they do not disable the ability to lock the door from inside. If the doors are locked from the inside, the door handle locks do not have the ability to unlock the doors.