What's the deal with front discs?

[Mister_Ee]

Are they all interchangeable or did they vary from year to year?
I just got some Brembo front discs supposedly off a 2006 Raptor 1000 and tried fitting them to my 2001 Raptor and the internal diameter on the carriers is a couple of mm bigger on the new ones.
WTF? I saw a post from Wierdo where he made some spacers but this looked like it was to fit Yamaha discs, do I need some or will the bolts hold the disc in the right place?

[Miz]

As far as I know the discs are interchangable, if your new disks have a larger ID then they are not for a Raptor, I would not be happy running the discs in that state, although the bolts would be more that enough to hold them in place, you would need to ensure that the discs were running centred/concentric on the wheel before the bolts were tightened up.

[weirdo]

Mister_Ee, you have a PM.