When I did my gears (70,000 miles or so) I got the master kit. Its going to be torn apart so why not replace all the bearings so you don't have to get it torn back apart again to replace one worn out bearing, that would suck.
Just make sure you have a way to press the pinion and carrier bearings on. If you do, go for it. I did all the bearings in my wife's car (and races) and it wasn't too bad.
Yep, replace all the bearings and seals. A ounce of prevention is worth a pound of cure. I made that mistake ONCE, 1000 miles later with a loud grinding noise I was back in there doing it again.