OK its only a year and a half later, and I'm finally getting around to putting these on my truck, but I've got a question about the bushings too. The stock springs have the eye, then a thin metal shell, then the oem rubber bushing, then another metal sleeve, and finally the bolt. But these new ones don't have the thin metal shell - just the eye, the poly bushing, the metal sleeve, and the bolt. Do I need that thin metal shell in these new springs?