You're looking way into it.
They're the way they are simply because of cheapness of design. There's nothing special about the seats. Like a lot of other items on Fieros, GM picked the cheapest items they could get their hands on. About the only "design" features the metal itself in the seat serve is to hold the upholstery's shape. However, as most owners know that have owned Fieros for a long time the metal in the seats can be a detrimental issue, such as the left side top bolsters wearing out on driver's side seats from getting in and out.
[This message has been edited by Fiero84Freak (edited 10-13-2012).]