First thing, since everyone's busting your chops on your user info in the sidebar, I'll join in, too... your avatar is too big. We ask that you use ones no bigger than 125x125 pixels - and your current one is too wide.
Second thing, what you're looking for with the mirror is to see if these screws have plugs over them or not:
If the plugs are still there, it's probably never been tampered with and will tend to be cold-blooded and too lean when warmed up. If the plugs are gone, someone has tried to make things better and may or may not have set it up right. It may or may not have a jet kit, but if it does, there's also a very good chance the airbox will have an extra 2" hole in it.