I have been messing with these old trucks since the mid-70s. My cousin and I have worked on dozens of them and bought parts from many more. I have never found an engine crank in any one of them.
We asked a lot of old-timers back then who worked on, or owned them when new. The word we got was they didn't come with a crank. An electrical powered crank was used to turn the engine over on the assembly line. That is why they have a place for a crank in the front. They said the compression was too high to safely start them with a hand crank.
I'm sure some entrapreneur may make a crank and call it a reproduction of the original. I have never seen an original hand crank. If anyone has found an original one, please post a picture. I would like to see one.
With the hundreds of trucks represented on this site, if original cranks exist, there should be several pictures forthcoming.