The third Avanti sold to the public, 63R1003, is available. It was donated to the Studebaker National Museum, and the museum is now auctioning it through the Hagerty Marketplace with no reserve:
https://www.hagerty.com/marketplace/auction/1963 -Studebaker-Avanti/a674bfb8-d821-492c-97ff-496058ccb07a
The car is pretty rough. White with orange interior. 289 with serial number RS1003. Body 63RQ 105. 4-speed manual transmission, power steering, power brakes, twin traction, aftermarket AM/FM radio. The supercharger was removed at some point and replaced with air conditioning.