Simply Maya User Community - mirroring geometry

Ive been following tutorials and excercises from books, but im getting to the point where i really need to just start making stuff off my own back to test what ive learned and to force myself to freely discover my own obstacles and overcome them. Ive set myself the task of making and then possibly animating a keyboard that sits in the room by the computer at which i write this. I'm making the keys for the keyboard right now, and as you know, there are four shapes of white key on most keyboards. one full size one, and then three different shaped ones depending on whether there is a black note to the left, right, or both sides of it. Ive made a simple key model for the key that has a black note on the right side of it, so what Im asking is... how can i go about duplicating this key to make a key that fits the position of having the black note on the left side of it. if that makes sense? I know how to duplicate objects, but its not as simple as that obviously, and i thought about duplicating and then rotating, but the object is bevelled in certain places that would make this a no-go. Im thinking about the mirror geometry tool, but I've never used this. I clicked on the key in question and clicked mirror geometry, a tab came up in the attributes editor, but i kinda hoped/expected the mirrored object of the original to appear, which it didnt. If anyone has followed this and can understand what im getting at, id be glad of some help. ..