Many years ago, I saw a book on early T-Bird parts. It listed the T-Bird part and part number, then it gave the part number for the exact same part for regular Fords......like park light lenses, taillight lenses, gauges, shocks, brakes, drivetrain....and the regular bits were half the cost of those for T-Birds. The engineering numbers on the parts were the same (close to a part number, but different) so it was Ford re-boxing with different part numbers of the same part for double the cost!