Nope. K code HiPo Shelby GT 350's. Shelby had a 427 supercharged Cobra. I think Bill Cosby bought one of those but sold it real soon as it was too much.
Late '50's Thunderbirds with the 312 could be ordered with a McCulough centrifugal supercharger. Later became Paxton.
The GT350S was paxton supercharged. SO it wasn't the Hertz. I got that part wrong. But the GT350S was a package. I'm not arguing semantics here. I'm saying there WAS a supercharged early Mustang. PERIOD.