In the first few minutes of the show the UNCLE car is stopped by barrels in the road and a pursuer's truck crashes beside it and the occupant is killed. A minute later when Solo is led out of his car, the burning truck (and all signs of it) is gone along with the dead body and the position of his own car has moved relative to the guard rail.
When Napoleon Solo is taken away to carry out a mission, he is provided with a red convertible sports car. However, it's evident there is no windshield in the windshield frame. First, as the car is being unloaded off of the truck, there is no reflection of sunlight on it. And second, when Leslie hops out from the back seat, she steps into the front of the car. As she does she grabs hold of the windshield frame for support. At this point you can see her fingers go through the frame where the windshield should be.
During the poolside scene with Solo and Mandor (Jack Lord) the camera equipment and lights can be seen reflected in Jack Lord's sunglasses.