Normal install kits do not include new pinion bearings, pinion races, or carrier bearings.
Master install kits include pinion bearings, races, AND carrier bearings.
Depending on how many miles are on the jeep, and weather or not you have the tools to remove the pressed on pinion bearings without damaging them will determine if you NEED new bearings or not. My jeep had 18k and after a bit of debate, I decided to opt for the master kits and install new pinion bearings. I didn't want to risk damaging the pinion bearings while pulling them and not have a back up plan.
You can also opt for standard install kits, and locally purchase your pinion bearings and races seperately, then when you get to that point, if you get the bearings off and back on the new pinion without damage, return the new bearings for a refund.