The perk "In Shining Armor" doesn't actually do anything. The perk was supposed to give the player an additional +5 Damage Threshold against energy weapons while wearing any metal armor, and +2 while wearing reflective eyewear.

The perk doesn't provide any Damage Threshold boost due to the fact that the parameter that is referenced when checking the skill type of enemy weapons is "Energy" instead of "EnergyWeapons". This means that the function "IsWeaponSkillType" will never return a value that can activate the perk effect, because there is no weapon skill called "Energy".