That's actually an interesting question from a metallurgical perspective. I probably should have some insight into the subject given my engineering education, but I can't say that I do. I'll contact a materials guru that I know and see if he has any insight...
If you describing the physical contact (i.e. exterior marks) on the splines then it would make sense that putting the force on the opposite side, but where it gets interesting is if the splines have been pushed beyond yield and have actually deformed (i.e. twisted) then I'm not sure that turning them around could be of benefit and they should probably just be replaced all together. This same thought would go for the twisting of the axles. It's normal for them to twist in as long as the stress doesn't exceed yield, and once they have been pushed beyond that they should probably be replaced as the physical properties have been changed. I would guess that they would become more brittle.
I'm curious now...
