I doubt this is the new GT500 unless the government relaxes the upcoming emission / CAFE regulations. With the death of the supercharged V8 after 2023 Ford is going to need time to develop whatever the next GT500 will be. Probably a hybrid if not all electric.
I think this is will be Boss variant. Those look like Mach 1 tips-the walls look thicker like the Mach 1. The Mach 1 allegedly was a Boss until they had to do damage control on the Mach name after putting it on the imposter.