Light Armor Concentration passive - do NPC enemies even have spell resistance?

Dagoth_Rac

The Concentration passive under Light Armor lets you ignore some of an enemies spell resist. Does it help against NPCs? Or is it really only for PvP against other players? It seems like my attacks do the same damage against all NPC enemies, so I am not convinced they have spell resistance. If they did, wouldn't I do different damage against different enemies, depending on their spell resist? I don't want to waste skill points on this passive if NPC enemies are just defined by health and how hard they hit, and don't even have spell resistance.

kelebra

They all have a base amount of spell resistance and I think it's pretty much the same forlike every basic npc. Idk what the value is, but it would explain why you see no difference between npcs. Plus it's not much to start with.