Yeah, I'm fairly sure this was entirely intentional. Fits the futuristic western sounds nicely.

Intentional or otherwise, the waveform certainly clips— you can see it in any audio editor, eg: http://imgur.com/a/WacOy

Since the drums sounds all started life as hi-fi samples, the detail is certainly there in the original Logic sessions. It would be an interesting experiment to do a listening test comparing the CD versions of the tracks against versions mastered with more headroom, either less loudly or to a 64-bit format.

It may well be that a certain degree of the grunge is artistic versus technical, but I suspect that in a blind test I would still prefer a version with slightly less muddy drums.

It also fits quite well with where those tracks typically play during the game.