There are a couple of scenes where Meryl Streep is riding in a pickup truck as a passenger. When the camera is on her keep track of the scenery that is rolling by in the background, after awhile you will see the scenery repeats itself several times.
Even better is the vintage of the cars seen through the rain soaked truck windows during this film set in the 60's. A 70's Cadillac and a 90's import can be clearly seen as Clint and Meryl drive around crying.
Being a native Iowa farm boy I spotted several slipups in this movie.
When the main characters are on their way to the bridge during the first outing they pass a farm tractor.
That tractor is clearly a late model John Deere with a modern "Comfort Cab" produced in the mid to late 80's.
Also on a few occasions in the back ground can be seen the large round hay bales, The machinery to produce those was invented in the mid 70's.
In one scene Francesca is seen coming into the drive way driving a John Deere 4020, Im pretty sure the date given for the timeline of the movie was 1963, 4020's were first produced in 1964.