There were close to 4500 Avantis manufactured, and roughly 2200 Studebaker dealers at the time, which would average two Avanti's per dealer. Of course it never worked that way, a dealer maybe selling ten, and several selling none. Even a dealer that sold ten would never inventory a stock of 'Avanti only' parts, and would have ordered them from a Parts Depot. I would not be surprised one of the many reasons R-series engines were offered across the board for the 1963 model year was to get more of them out in the field where dealers would stock tune-up parts for them.
Craig