anyone know if this would work? (i have an older install of the game)

[Perjoss]

around 3 months back I made a copy of the fallout 4 install directory as I wanted a clean version of it in case my modding got out of control, I figured it would be the easiest way to revert to vanilla without having to download the game again.

Anyone know if i simply replace my current install folder (it has the latest patch installed) with my older clean install and then set the option for steam to not update, would that keep fallout 4 as its pre-patch version?