[PF] Skeleton Weapons and CR?

[Arutema]

The standard cr 1/3 pathfinder skeleton uses a broken scimitar, which means -2 on all its attack and damage rolls.

If I were to replace this with an undamaged longspear, effectively giving it +2 attack and damage as well as reach, how would this change its CR?

[Runestar]

It's probably not enough to warrant a cr increase, IMO.

[Shpadoinkle]

I'd bump it to 1/2 CR and call it good.