If you want a set of chrome ones you're most likely going to have to have them custom made. I have seen only one set of all chrome 67-68 style badges the entire time that I have been keeping an eye out for them. The NOS GT 350 badges from 67-68 should all be the chrome and gold color scheme. Here is a set on ebay in case you are interested:
The normal price for the NOS badges are around $45 - $50 per fender emblem and around $65 - $75 for each grille/ rear decklid emblem.
If you are interested in having a set custom made you need to speak to Mike at MTM Custom Laser ( http://www.mtmunlimited.com/ ). I have seen plenty of custom GT 350 emblems that they have made for fenders, decklids, faux gas caps, and steering wheels. He should be able to make you something nice that would probably look better than having the NOS emblems on your car at a fraction of the price.