I don't think there's a full kit since it's a smaller application than a 1500 truck, but you can get a front kit and rear kit separately.
Flip kit - Belltech 6605 and 6650 can't tell the difference, and 6607 includes carrier bearing spacer for extended cab trucks with the 2 piece driveshaft. All three of those show to be flip kits for a 454SS so to clarify what the exact differences are you should probably contact Belltech. It's been about 11 years now since I bought a flip kit for a GMT400 with a 9.5" 14 bolt rear, so my memory is a little vague on which part # I picked..
The front parts you would use the same spindles and springs as a 1500 with HD brakes, in other words 1.25" rotors instead of 1". (The 88-89 1500 reg cabs had non-HD brakes with 1" rotors and use a different spindle.) Your 2500LD already has HD brakes regardless of cab type so pick spindles and springs for an extended cab 1500.
Richard