The Renault with the two Frenchmen has no rear view mirror during the interior shots, but facing the car the rear view mirror is there.
When Rockford goes to the Renault after it has run off the road, the lightning banks are reflected on the car.
Early on Buddy Richards is explaining what Carinhall is-he says it is Goering's place in the Black Forest-it is actually the opposite direction from Berlin-Northeast as opposed to Southwest as the Black Forest is.