Good point, I never thought of it that way. That means the pre-West Coast versions are "originals", which means they should command a premium out at Barrett-Jackson.
It's believed that the original molds and jigs used by Kellison and up to the West Coast era ended up at a company in Nuremberg, Germany around the mid-80's time frame and the trail runs cold after that.
The West Coast frame and interior have been upgraded. The front suspension is a coil-over with improved geometry versus the original Mustang-II based front suspension.