No, Giants Ledge is near (just east and north I think) of Slide Mt. Giants Ledge is one of the highest and more scenic places you can camp in the area, which is one reason it's popular.
Since I writng again, my impression, and thats all it is, was that there might be a few one pitch routes. - more for fun and the setting than the climbing itself. The rock quality looked good - like compact Gunks rock, but it might not connect up from top to bottom, and didn't look to have horizontals and the easy protection of the Gunks. Still it would be fun to camp and climb at your door!
I was interested in exploring, but not expecting much.