nope, I can't remember but I might have had to lossen the tension on the strings at the most, the mutes fit over the bridge then you just have to screw on the thumb screws, pretty simple.
Yes remove the bridge to install the mute plate and thumbscrews.
If you try it with the bridge in place, all you'll be doing is gouging up your finish.
Oops, yeh I guess removing the bridge is a good idea afterall if you're conserned about your paint job, for some reason it didn't cross my mind when I got my mutes....