As far as I know, it works for all gametypes. All luas are setup basically the same way. I think the only luas where you might need to do anything different is with a space lua. I believe the placement is different for those.
As for .bak files, that's nothing special.

It's not any sort of proprietary format. That just siginifies it's a backup. Remove the extension, and you have a working lua, though you may have to do a little more work to add the mode fully, which I won't go into here.
Btw, turn off "hide extensions for known file types".

You're more likely to activate a virus with that on.