These knots could possibly be practical or functional, but I believe they are more suited in the decorative section. From "Hogan's Heroes", season 2 episode 3, these images are taken. and I wonder if there is more light to be shed on the knots shown.
Not being a car enthusiast, I don't know what make, model or year the car is. But in it, just behind the front seats, hang handles for the back seat passengers to grab. Also, there is some sort of ornament by the back seat. It is only briefly showing and I didn't manage to get a better image of it.
Any information would be great.