Start it and press the starter again, if you get a menu option for the grips then they are installed. You can also check the grips themselves, headed grips are have a hard plastic ridge in the inside with a recessed screw that holds them in place.
i just added heated grips to mine and took it to the dealer to have them turned on.. (works great) but like the previous person said, its obvious, when you push the start button with it running, a little box menu pops up.