Well, I can see how it *could* be of concern. Correct me if my logic is wrong here... I've never rebuilt a diff myself but I understand what's involved.
When you set up a diff it's not under load. You check the pattern to make sure the gear teeth are engaging properly but when you put it into service things are going to shift just a little bit due to the much greater forces involved. There is clearance and play under load that can't be duplicated on a bench. So, the teeth start to wear together in a certain pattern on the driven side, and in a different pattern on the coast side because the forces being applied are coming from opposite directions. Now you change the direction in which force is applied and the coast side becomes the driven side, and vise-versa. Because of that little bit of clearance, and because of flexing and play that simply cannot be eliminated, and any wear that has occurred, the teeth will be wearing against each other in a slightly different way than they did before, contacting each other at a slightly different spot, and the loads have changed direction.
I can see how this *could* lead to accelerated wear and noise. Will it? I dunno, guess I'm about to find out.
In the meantime I'd like to get started rebuilding the broken diff - where's the best place to acquire gears and rebuild parts?