Recently picked up an aluminum core support out of a 78 Regal that also had the aluminum trunk lid. Recently found another 78 Turbo Regal on Craigslist for parts and thought I was going to find another aluminum core support but was disappointed. It was strange that the car did have an aluminum trunk lid. Has anybody else encountered this. The owner said the car was all original. What determined that a car would get an aluminum core support?