I believe the stock spring bolts have male splines on them that line up with the female splines on the stock shackle. They are supposed to come apart, but hardly ever due. I've done a few trucks, and I've had to cut half of the bolts off. A new stock shackle "kit" is like $50. They don't sell the bolts or shackle separate, just as a kit.

88 4R, 350 V8, R150 5 speed Sold <...uot; />
97 4R, stock, daily driver
98 Sienna, kid and dog hauler, wife's ride