New member to the forum, saw your post. No one responded to you since you put it up in 2005?
The 65 Shelby Mustang had very few cosmetic changes over the stock fastback. The Shelby mods were suspension, seat belts, some emblems, stripes, and remove the back seat. You can find all those parts today to do your own version. Although if I was going to do a project like that I would lean towards updating things like a 5 speed. It can look like a Shelby but it is NOT so why be concerned about keeping it like the original when you can make it much more fun to drive? By the way I own a 68 GT350 which I have keep pretty much "stock" well more or less.