In the opening scene, the grille of Buzz Larkin's stake truck has only a single vertical strip of chrome. When he arrives in town, the truck is a more expensive model. The grille now also has chrome horizontal bars.
After the safe is opened it can be seen there are no locking bolts in the door, revealing it to be a prop.
After the truck is stopped and just before the officer frisks the truck driver he puts his service revolver inside his pants next to his belt. A trained officer would never do this.