Short answer - yes. Body lifts make the car more "tippy" (just like any lift) so bear that in mind. Also bear in mind that you're going to have to make or buy pucks for a body lift.
It's actually easier (if you ask me) to do a spring over axle conversion. You just need some 50x100x3mm box and a good welder. If it's a Samurai rather than an SJ413, then you just cut a hole through the box section, cut that in half to make the perches, and weld it to the axle. If it's a 413 (non sammy) then one of your perches needs to be wider on one side because the leafs are set closer together (one of the front ones rests slightly on the diff):
*Edit* I stitch drilled that, so it's got rough edges. I used an angle grinder to smooth off the edges then bevel them ready for welding to the axle.
I say this because then you can sell the shackle reverse kit and you should be a few quid better off.
If you can't weld or just don't want to, then a body lift is fairly simple, it's just awkward and the body is *HEAVY*. It's only held on by (if memory serves) 6 or 8 bolts.
Just take a bit of ally bar, drill a hole through it the same size as the bolts you're gonna use, jack the body off the chassis enough to slip them in, and then drop the bolts through. I *think* some of the bolts are captive, you'll have to angry grind those off and drill through so you can use your own bolts instead.