Is gravity the same at elevation? The ball falls less fast in Colorado then it does in Florida.
The theoretical answer is yes.
The effective physical answer is no.
Decreases in air density which lessens buoyancy mitigate the gains.
So, at 30,000 ft (The top of Mt. Everest) While you lose 0.29% of the effects of gravity, the change in air density makes this 0.08%, or about a quarter of the gravitational effect. As the change is roughly inversely proportional to the square of the change in height, 1/3 of 30,000 or 10,000 ft, about as high as you'll ever build a golf course, that is roughly a 0.01% change in gravitational effects.
http://en.wikipedia.org/wiki/Gravity_of_Earth