When I write up an NPC I usually specifically write down the Physical track. This is just because the Stun track isn't really needed 9/10 of the time. If one of the characters decides to start doing Stun damage, then I just jot down the Stun Track next to it.
However, since I started using Hero Lab's combat tracker... I haven't had to bother doing this, since I can just click whatever damage track I want. Makes combat really easy to manage.