Any data you want to persist between game sessions needs to be stored in your game save.
For the system I designed for you, you need to keep all of the variables we built into the game instance in the game save as well. The GameInstance data persists between levels, and the save game data persists between game sessions.
When you save the game, copy the current values from the Inventory, Armour/WeaponActive? and ActiveArmour/WeaponID in the game instance into your game save. When you load the game copy from the game save to the game instance.