I use a mangled version of body hits, basically capping raw damage (not injury) to the torso by piercing/impalting at 1xhp because the overpenetration rules state that's the point that they blow through. Also because the damage for guns is somewhat obscene.
The 'stopping the bleeding' rules are stupid because internal hemorrhaging already requires a nearly field-impossible surgery roll.
We often play with some fantastic elements, so I don't se those limb hit rules because frnakly cutting damage doesn't need any more random fucking advantages.
I roll firght/will for NPCs pretty often in such situations, yes. I usually let it slide for players unless 'never been shot at' is part of their deal. I might consider it depending on how bad the wound is, but RAW firearms rarely leave anyone in the realm of combat effective where the fright check for being shot would matter.