Really like your investigation and thumbs up for these old Campa parts. I was stunned too when restoring an old set that never saw any love by the previous owner (and never changed anything like your cable was). Some parts looked terribly bad but after a good clean it was working like new. Only a bottom bracket was pittet so badly it needed replacement, but further it was nearly none Italian quality. Shifting with those bullet twisters is a bit tricky though.