The GT does not have c-clips like the article on the Bullitt Archive shows. A Haynes manual would be helpful but also only shows the c-clip fasteners on the caliper.
I can't vouch for that for sure, but the basics should be the same. I've changed many disc brake pads on different flavors of cars (even done some drums, which are quite a bit different) and they all pretty much follow the same steps. I had bought the haynes also but it didn't cover exactly my stang even though the book was for the correct model and year. So this link helped me out quite a bit.