I played with the lock on the passenger door and figured out how to lock up the truck. I push the drivers handle forward (from inside) then crawl out the passenger door to turn the key on the passenger door from outside! That was pretty funny as my wife laughed when she saw me trying it the first time. I know it might not stay safe but atleast I can lock it now.
It was interesting to figure out given our modern methods to lock a car(I push a button on the remote in all my other vehicles. However given the 1951 threats, I guess not many folks really bothered to lock up a truck back then...