If CDC would manufacture this grill for the 2007-09 model GT500's they would sell as fast as they could make them. The factory grill is pretty ugly and terrible to clean/ detail, if CDC decides to make these count me in.
Maybe they think nobody would like to relocate the horns, etc, in order to make it look right, as I can't figure out why this one wasn't done long ago. They have the capacity to digitize the '07-'09 grill perimeter, put it into CAD, sketch up a grille that looks right and simulates that of the '13-'14, rapid prototype an upper/lower, make a mold(s), and start selling them. It isn't rocket science and for a company already setup to do it, such as CDC, it isn't cost prohibitive and my guess is they'd be able to offer this at a reasonable price point and easily meet their break even point quite early.
Same goes for a '13-'14 style tail light for an '07-'09 that isn't tinted...