I haven't done a body lift on a Chevy, but in addition to the 4wd shifter you'll also need to consider the radiator. It might require dropping.
In some trucks I've also seen engine components become inaccessible after a body lift due to firewalls being moved.
Generally I'd recommend against a body lift unless you have a really specific reason for needing it. A suspension lift is usually the way to go, despite the higher price.