Player Model Material Overlay

[Axspeo]

Hey there,
Is it possible to set a material on a model without actually replacing the original textures?
So I can add some transparency to the overlay and achieve something like this:

https://files.facepunch.com/forum/upload/169640/22753284-a91f-4823-9e28-30b86883775c/overlayed.jpg

Thanks in Advance

[Gmod4phun]

This can be either achieved with stencils, or a more simple way would be to use render.MaterialOverride