Upgrading to BNW on Steam but playing GAK conversion mods

I am using a conversion mod (GAK version of Nights), but want to check out Brave New World. I have the game (with Gods and Kings) via Steam... if I upgrade to the new expansion, will I be able to revert back to GAK/Nights? If so, is there a trick to it?

I just don't want to lose the ability to play Nights if I don't care for BNW!

(Sorry if this is a cross post, I just realized I might not get a reply in the Nights folder.)

Thanks in advance!

After you install BNW, you can go to the DLC item on the main menu and de-select BNW.

Also, if you open up a G&K save file it will automatically load just G&K.

That's perfect and great to know - thank you!!