Charmed Pet Gear (non humanoid)

[Nyvoren]

As most of you are aware, the lower the MR of a pet, the longer the charm will last. If an animal pet is given a weapon, they do not proc, nor does the damage type change, but they do have the item on their corpse. What I am curious about is if they ( or anything that doesn't hold weapons ) can still be affected by negative MR gear for the primary / secondary slot ?