Here is the nice picture from one of these sites:
I'm pretty sure that is an aftermarket axle.
One site stresses keeping the axle rotation the same. Sort of like the advice we get for torsion bars - reinstall so they are stressed the same way they have always been stressed, because reversing the stresses is a bad thing.
I thought that ought to apply to axles, and marked the direction of rotation with tape on them. Then, some 10 or so years ago, Porsche put out a technical service bulletin for those racing their Cup cars, advising that the rotation of axles be changed when through half of the races for that season. I guess that axles see force reversals more than torsion bars do. I checked with some engineer types, and stopped worrying about which way my axles go back in. But I follow the usual advice with the torsion bars.
These sites stress cleaning out the bolt passages, threads on the transmission flanges, and the bolt threads. I've given up worrying about this, because to me the work involved (tape over the bolt holes, a sequence for greasing the CV) isn't worth it. Bolts stay put because they are stretched appropriately. Some grease on threads means they will be stretched a bit more than if there is no grease for the same torque wrench setting. I'd rather have more, and it won't be enough more to cause them to exceed their elastic limit. What I work to keep grease off of are the mating surfaces of the CV and the flange. It is the friction between these two created by the tension in the bolts which prevents the CV from moving even a micron against the transmission flange, and I don't want to reduce that friction.
Of course, if you want a thread locker to work, everything has to be clean.