IIRC, the "new" sig. model is a copy of his #1 Ibanez RX that he modded, which is probably
why it may look like a starter or lesser quality guitar. The story behind that guitar is that
he bought it at a "fire" sale from Brook Mays Music in Plano, Texas, where I worked many years ago.
The building had burned, but some of the guitars remained intact. The legend at Brook Mays was that the smoke from the fire did some mojo to the wood of that guitar and he specifically chose it because of its tonality.
I wasn't there when it happened, so some of the facts may be off a bit, but I think generally that's the story.