Blueprint Assets references will be always in memory?

When I use UE3 every asset reference that I’ve in scripts for example - Texture2d’UI.UI’ will be always in memory on Mobile.

I’m curious if the same thing is happening in UE4 blueprints. For example Set Material, Set Mesh - they will be in memory all time on Mobile or only when executing blueprint?

I want to create weapon changing system and I will have like 20 different materials with 1024x1024 textures in blueprints.

anyone can answer this?