It's hard to tell from those pics and I'm not going to look for it on FB, but all I can see is a color that wasn't available on it and some wheels that could be swapped in 15 minutes or less.
That said, I would be very unlikely to pay $4K for a car that had no engine in it even if it was painted the original color, had the original wheels and had whatever else it was supposed to have. This hobby makes me shake my head sometimes. I mean, if Plum Crazy was the factory paint color on that car, everybody would be praising it as a beautiful and rare car. There would probably be people saying it was a good deal at twice that much.
When my car was completely stock it actually got quite a bit of interest.....from the derby guys! As a matter of fact, they were the only people who showed any interest in it at all. Now, with just a few very mild custom touches, I get people complimenting it and asking me questions about the car itself and not whether they can buy it as a derby car. I have no intention of yanking my engine and trying to sell the body, but if I did, I wouldn't expect to get offered more than $1K or so either, regardless of whether it was bone stock with original paint color or not.