if it were a saxophone there are only so many brands that could have made it but a clarinet makes things way more complicated.
Rampone & Cazzani certainly made many clarinets but in 1965 it is way more likely that it was an Orsi. I am not familar with the stencil brandname " centaur" does this clarinet have any distinctive features?
you may want to contact the Bate's collection
https://www.bate.ox.ac.uk
I am afraid that if the clarinet has no distinctive feature you may never discover who made it
Rampone & Cazzani certainly made many clarinets but in 1965 it is way more likely that it was an Orsi. I am not familar with the stencil brandname " centaur" does this clarinet have any distinctive features?
you may want to contact the Bate's collection
https://www.bate.ox.ac.uk
I am afraid that if the clarinet has no distinctive feature you may never discover who made it