As long as both are coil spring front suspension you'll be fine for the front. As far as the rear. Flipkits and shackles are going to be the same. But if you need to swap hangers for any reason (6" is typically JUST a flipkit) the hangers are different. Also he probably has a carrier bearing relocator for the 2pc. driveshaft while you have a 1 pc. So in reality yes you could trade, but hes not going to need much off your truck besides spindles and coils up front and out back he's better off getting a brand new set of ubolts.
Ubolts are designed for one time torque and stretch so they recommend you replace them.
As far as the carrier bearing. You just won't use it.
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