Instantiating a renderer and its materials as a backup to swap due to highlighting

I'm just wondering if what i am doing is correct and efficient.

I'm instantiating a backup of the renders and it's materials found within all sub meshes of a game object that is to be highlighted with an extra material and a color applied to the existing texture and then reverting to the backup copy i made on Start().

It works but it appears Unity will create the entire object and i found a pile of these objects at 0,0,0 in the world.. i simply added a enabled = false to them .

Is this normal and the best way to go about applying and reverting to a different effect to meshes?

As so far i am only working with a handful of objects and not an entire world full is this standard practice? it seems essentially i'm doubling my object count.