The Garhauer equipment didn't start appearing on the C30 until the Mark II version in 1986, replacing the old Seaward and Nico stuff, including the curved traveller.
http://www.catalina30.com/C30Yacht/C30Yacht.htm
I know you may like the look of the curved traveller, but there was a reason it was discontinued...... they perform poorly..... by pullling the boom down when shifted to the outboard position the mainsail twist is changed, defeating the whole purpose of having a separate traveller and mainsheet...
Garhauer will hook you up with a dandy, modern system, they are an excellent company.........
www.garhauermarine.com but if you're absolutely jonesing to reproduce the curved track, you might give Catalina Yachts (i.e. the factory) a call to see if they have any in their parts inventory..... remember...this boat manufacturer is still in business and is widely known for their ongoing service to all Catalina owners no matter what the boat's age.
www.catalinayachts.com