Yup it's fine, the 8800gt ran a notable bit hotter then the other 8800 series. Still, keep an eye on the temps. If you start getting lockups, black screens, ar your temps start to approach 100c then best to clean it good before it fries.
If you want to try improving temps, check to see if there is any dust build up inside the gpu heat sink. With the computer off you can try spraying a can of air in there to try shoot some of it out. You may have to pop the plastic shroud off to get in there best.