It's not too surprising that the devices have different names on different operating systems, but what about the fact that Acidnine wrote a config for a controller named [XBOX 360 For Windows (Controller)], while guran wrote one for [Controller (XBOX 360 For Windows)]? That's pretty strange.
Not if they are using drivers made by completely different people. To narrow it down you probably need to know the driver used before blaming anything else. I wouldn't be surprised if Microsoft had different teams doing drivers for x86 and x64. Also it is a popular controller, meaning theres 3d party drivers circulating.