shouldn't the faces of those teeth be worn in / polished shiny? looks flat and dull in the photos. how many miles on them?
I had the same thought too; normally I see them polished shiny but maybe that takes more miles? Probably 10k miles on this ring and pinion.
Honestly, I've never had a differential open with that few miles since rebuild. Usually I'm not pulling a cover off until at least 50k or more miles.