Maybe I've got the Gibson Custom Shop wrong, but if they're using higher quality mahogany etc I would have thought they would say so?
Don't want to get too embroiled in this, but I would assume Gibson
do use better quality timbers in Custom Shop/higher priced models, because.... that's what you do in a Custom Shop, isn't it?
I agree they don't make a point of saying so, but in their promotional materials generally they
never really say much about timber quality, number of pieces of wood in a body etc. It's just their style.
When I had the Pete Townshend SG (which wasn't the Custom Shop one, just a high-end production model) it had a very high-quality one piece body, better rosewood in the fingerboard etc. Whereas my cheaper Gibsons have had two or three-piece bodies.