My understanding is that Cambio Rino bicycles and equipment were made in Ossona, Italy. Gardin was simply the distributor. The Cambio Rino parts were also marketed in the USA under the Excel name. Later Gardin manufactured mid and high end road and track bicycles under his own brand, though distribution was limited.

Cambio Rino parts are hard to find, but I believe I know where there is a used crankset and a NOS rear derailleur.