As stated before, the car isn't a special edition so do what you want with it, if it makes it cleaner and nicer it will help a re-sale, but won't change the value very much.
And definatly no, that interior is not original. It's probably the two tone vinyl kit from latemodelresto.com. I'm pretty sure the whole interior was blue with blue cloth seats and someone just changed the seat covers.
Personally, I would change the interior color to black or white, or black AND white, and keep the car white with a black top.
You can pick-up some vinyl seats from LMR for around 300.00 and paint the plastics. Thats about $2200 shy of a decent paint job when your changing color.