Is an activation code needed for Total War Shogun 2?

I found a secondhand copy of Total War Shogun 2, which came just with the overall guide to the game, introduction, installation, commands, etcetera, no code.

In the installation guide, it says an internet connection is needed for the initial installation, and for multiplayer, Windows needed, but no mention of an activation code or something.

Someone wants to buy it from me, but neither he nor are are sure if some kind of code is needed first, any advice?