The bearing cups in my joint were pressed very firmly into the yokes - so I didn't need to put the circlips back in. If you grind down the pressed bits, you *probably* won't need any retainer either, for reassembly.
If he's trying the access the hole on the joint to attach the dowel, there's no need for that. All he needs to do is grind the bump, the round bulge in the center.
True, but I would prefer to avoid grinding dust getting into the bearings (not for longevity, more for the feel). It would probably be unnoticable, but it's not *that* much work to disassemble the joint.