I think that is the most common spot as I see them ( or at least the remnants ) placed there all the time on many makes and models. Even today I still find them on late model cars in that spot.. of course todays are much differant. Problem is that those springs make the build sheets look as if they went through a paper shreder and most of the time only a few pieces are left.
I think the next most common spot is behind the rear seat back.