I don't think this was ever a factory installed mustang tire. However, my father came to posses this vintage tire while collecting parts for a recent mustang restoration.
I believe these are the size/brand tires that came installed on some ~1970 cudas and challengers, but I'm no Mopar enthusiast. As an original tire, however, I can't help but believe someone out there might be looking for it for their restoration.
Tire appears to be in good condition, however, I would not trust its' integrity for any significant on-road driving (show only.) It would likely make an excellent spare.
I've seen similar tires for sale on e-bay at $449.00 (who knows if they sold.) I'd be happy just to see the tire end up helping someone with their restoration project... $375.00 obo.