Maple is generally quite hard to stain. It tends to absorb very unevenly and leave you with a splotchy result. This is on freshly installed and sanded maple. Generally all you can do it use a wood conditioner first and hope that helps control the penetration of the stain. The problem there is that wood conditioner keeps the stain from taking the depth of color it normally would. You'll have to experiment to get the color you want. In your case, it sounds like it's already been clear coated so once you sand it down you may not have to worry about it absorbing heavily (unless you sand it quite far down.) Unfortunately you'll still have to test the color on your floor to see how it takes. If it were me, I wouldn't take a chance on messing up my floor.