Note that annealed case necks usually have discoloration on them as well as part of their shoulders. Many companies polish their cases after annealing so they look good for sales just like bullet companies polish their stuff. This usually gets rid of the surface discoloration and the case looks the same all over; outside and inside. Arsenal cases are not polished and their neck discoloration is easily seen.
Doiing hardness tests on cases is the only sure way to see how hard or soft their areas are.