Any of the extra grease has been removed. anything left is just in between the leafs. I did this before on my Cherokee springs per recommendation from Will over at Sierra Expeditions. Its more common then you think. When I changed out springs on my Cherokee I broke them down and the dust never made it in between the leafs. just some spots were it creeped in a bit.
A lot of the cheaper spring companies just use dry plastic discs, maybe plates or nothing at all. My Old Man Emu springs (for the Cherokee) came with teflon pads pre-greased. It was recommended to wipe that grease out and put in white lithium.
it's a damn smooth ride this truck. I'll have no complaints on the leaf springs.