Have you had it apart? Those are overload springs on top, they could be factory, but likely aftermarket, there's been a few discussions about overloads on here lately, but it's unlikely they changed the bottom factory spring holders. Pull the u-bolts loose and see how much comes apart, any trailer shop or spring shop will have new u-bolts.
I will bet the long u-bolts were changed and the upper overloads were added on top of the factory collars.
