You should but that's no guarantee. Unless you owned it from factory you don't know if someone forgot to put oil in it at some point or had a few burnout sessions. When you open it you will be able to inspect the shafts and gears plus the diff for chipped teeth and wear. That goes for anything though. If you get a new one you could keep your current one as a spare which you'll probably never land up using
Toyota driveline components are used for everything, the celica rwd box is put behind v8 monsters, the diffs are used in countless offroaders and rally cars. They are known for being reliable.