is this a good idea, i'm looking at buying a raptor that has this done to it. does this screw anything up? can i undo this, or was any kind of irreversible modification done to do this?

 

? Why the hell would someone put the swingarm upside down? I don't even see how it would work. Don't see how the pivot arm and shock could work. I'd like to see this!

 

Is this a stock or aftermarket swingarm?

You need to realize there is a threaded hole for the brake plate on one side of the swingarm. If its on the wrong side, you will not be able to use the rear brake. The sprocket has to be on the left side of the bike.

 

Are you sure it's the swingarm and not just the linkage?