Because of the inconsistencies in the angles, lighting, camera and grade of the pictures this is really hard to compare! I think we have to disregard all the red portions that are in photo #3 because they wouldn't be in sight because the angles of the other pictures don't show those same areas. The color is difficult because the hues will vary depending on camera, lighting and printing. The best way, I think, to compare the colors would be to compare the values not the hues. In other words to look at how the lightness/darkness (values) of each car seat contrasts to the interior of the car. (See how even the car interior "color" (hue) looks different in each picture? Well, the contrast between the car interior and the car seats look about the same to me . . . I don't think you can be very definite about it, though.
The only difference that interests me is the shoulder straps. They are either hidden in picture #3 or they are the wrong color. But I can't see where they go through the slots even when I magnify it to 400%. And as has already been pointed out, if they have been disconnected that means that the seat had been removed ~ which would be very suspicious!!
My observations are few and not enlightening enough for me to make a solid decision ~ but I've sure enjoyed this thread and all the work everyone has put into it!! Wish we could find more pictures for comparison.