I like the white interior. I believe it was only offered in leather, so Im assuming GTs only. I dont know about 95, but my 94 brochure said that white interior was available to all exterior color models EXCEPT white (which I find VERY odd) I have actually seen more cars with red interior, than white, despite the availability. I like the color, but I bet is a pain to keep clean. Thankfully ford allowed the carpeting and steering wheel to be black, unlike with the red, which was all the same color.
As far as the top goes, my car original came with a white top. Its rare for the same reason Iris Metallic mustangs are rare, as who wants one? Though the top was for years old, it was already showing its age. I kept it till it was 11 years old, and despite looking like crap, it still looked nicer than newer white top mustangs.
Thing is, its a mustang. Ford has records that it originally came with a white top, which you can have them mail you a letter stating that. Enjoy the black top. Should you decide that the car would be more valuable as a collectors car stock, there are hundreds of companies out there that can sell you a OEM quality top, just remember that 95 had pinpoint vinyl.