I've had offers back when I first got it for $10,000.
I'm told by several luthiers that Gibson has a straight slot for their truss rods now, instead of the curve. A few guys have had to remove the fingerboard in order to reinstall the truss rod correctly
IIRC Taylors have a traditional design truss rod that's put in a straight slot, but the slot slopes downward. So the right straight slot will work. I suppose it's possible that Gibson is doing this. Or not.
Gibson changed the truss rod design a bit, at least on the Memphis models. A bit larger & Teflon coated..........http://www.gibson.com/Products/Electric-Guitars/2015/Memphis/ES-335.aspx