Indeed, the one in the game is the same horn as the one shown in the video, but it's a bit better sounding in the game, actually. It also depends on your audio equipment of course, but I think it sounds perfect allready.
It might not be the same as in 1912, indeed, but I think it's about as close as anyone is going to get. So in this case I'd say the Titanic horn is as good as it gets, the way it is ingame at the moment. And this is why Terry and I both thought we should leave that one alone.
The game one actually does have a slightly higher pitch, which would be more realistic, and some 'rumbling' in it, which I would think adds towards realism too, as opposed to the one in the video that is blown with air instead of steam. That's just my view of it.
I think the game one is better, but that's a matter of taste, as much as a matter of authenticity, I guess.
Regards,
Fred
* edit * typo