Here's my $.02 on the matter;
Are you building the car for yourself, or someone else? If you're building it for yourself, I say build it how you want to build it. If you're building it for someone else, or strictly to re-sell, then original is probably better.
Case in point with my Chevelle; granted, it's nowhere near the status of a `67 Z28, but it's still a fairly valuable car. However, since it's no longer a matching #'s car and I have absolutely no intentions of ever selling this one, I'm building it the way I want to, which includes a color change from what's on the trim tag. Common sense dictates that I'm not going to do anything to the car that's irreversible, but it's not going back 100% stock either.
Build the car in whatever manner makes you happy and let others worry about their own cars.
Eric