When Henry calls Higgins at the general store to stop the dynamiting of Rad and Reeve's land, the lighting in the store changes. When Higgins answers the phone, the store is dimly lit. When the camera cuts to Henry and then back to Higgins, the lighting is almost bright daylight. After the camera cuts to Henry and then a final time to Higgins, the lighting has dimmed again.
In one scene, as the camera pans down the street, a later model Ford is in a carport.
The story is set in 1946, but an early scene features a Sikorsky S-55 helicopter (also known as an H-19 Chickasaw), which was first produced in 1950.
As Caine drives Law near the beginning, they closely pass several newer parked cars as late as a 1964 Ford in the post WW2 set film.