The "correct" factory wheels are just the 15x8 slotted stock wheels with the chrome trim rings and center caps that are available in the Vette accessory catalogs, JEG's or Summit Racing. Getting those mail-ordered to Australia may be another issue tho
Popular aftermarket wheels in the late 60's were the American Racing Torq-Thrust "D" and Torq-Thrust "II" as well as the Cragar S/S wheel.
American Racing makes the Torq-Thrust II wheel in custom offsets and backspacing so you could have a wheel made to fit the car if you intend to use larger tires. It's model CL205RWD on their website.
Here's a couple of links regarding the L88 car
http://www.corvetteactioncenter.com/...8/l88prod.html
http://www.corvetteactioncenter.com/specs/l88/