Trying to unravel a mystery. I have a 68 Firebird convertible. I believe the motor is a 350 but have not confirmed this. I am working on the rear end, specifically getting ready to replace the rear springs.

First off, it appears there is a "bow shaped" extra spring added to the bottom of my springs on both sides. I am assuming this is some kind of add on that someone has stuck on and is not a "factory" installation. Anyone have any thoughts?

Also, referencing the "facing front" pic and ignoring the "bow shaped" spring mentioned above, it appears I have 5 leaves in my springs. However, referencing the "facing back" pic and again ignoring the "bow shaped" spring, it appears I have only 4 leaves in my springs. The fifth leaf ends just after the saddle. This is the same on both sides of the car. Any thoughts or information would be greatly appreciated.