DTS is good to go; Ive built several rear axles/diffs using parts purchased from them, including bearings and other things like structural covers.A retired mechanic who I've used for rear-ends (he lives in Saginaw, MI) always gets his parts from Drive Train Specialists in Detroit ("DTS", https://www.drivetrainspecialists.com/about-us). For him, it's a 45min drive to DTS or a one-day ground shipment.
He claims their bearing sets are OE quality.
Bearing quality has been a recurring topic on GMT400.
YMMV, I'm just repeating what he told me. I literally drove to DTS from his house and picked up the parts he needed.
@Aidan Kesler - IMO, the trickest part about rebuilding/setting up differentials is getting the pinion depth just right. I have the Kent Moore ring and pinion set up tool which takes a lot of the guesswork out but if you don't, take your old inner pinion bearing and grind out the inner diameter of it so you can slip it onto the new pinion gear. This will help make trial and error fitment a lot easier.
Once pinion depth and backlash are correct, the pattern check should pass. Lastly, use a pinion spacer instead of a crush sleeve - I hate those stupid sleeves... Harbor freight has axle bearing pullers, seal/race drivers and OTC makes a good diff carrier bearing puller kit. You shouldnt need an axle spreader...