[squidtone]

DSMTiger,
since you're asking, here are some of my thoughts:

Are you thinking of a stock look, or a slightly custom look? Do you mean the DB red lines?
For stock 14" diameter look, keep in mind subtle differences in wheel offset can make a big difference in look. Stock 14 x 6 Rally I wheels had a narrow exposure of rim (offset) and indeed they need a narrow trim ring (which is hard to find for original Rally I wheels). But,last I knew, you can still get aftermarket 14 x 6 Rally I wheels, and the offset is close to original. And, the aftermarket wheels slots are slightly smaller to allow the use of normal, easily obtained trim rings. In my opinion, the narrow offset with accompanying narrow trim ring look is perfect for 64-67 cars.
If you go for a wider aftermarket Rally I wheel, with a wider trim ring, like a 14 x 7", or the 15 x 7" wheels, they have a deep dish look that (in my opinion) really changes the look of the wheel/trim ring/centercap combo. The six slots in a deep dish aftermarket Rally I wheel look lost to me.
It's personal preference!
Another thing too, you have a cool 66....1966 GTO's came from the factory with red-painted brake drums if ordered with Rally I wheels. You might want to paint your drums red....

Good luck on you decision.