I certainly wouldn't fault them for putting the story under source control/versioning or even the location they did it, but there'd be benefit in separating them into two different projects/solutions as you could essentially have a separate "engine" project that could be reused for future games and then different projects with assets/story/etc for any game that comes down the pipe.
Now, if the intent is a one off and they have no intention of drinking from the same well so to speak, go nuts.
If you need it version controlled there are two options. Use somthing that does versioning in the database (like django-reversion f.ex.) or separate the story into it's own repo and use it as a sub-module. There are other ways, these are just the two that jump immediately to mind.
