A quick google image search will reveal both trees that show some trunk and some that don't.
http://lmgtfy.com/?t=i&q=flame+style+ginkgo
I don't know that one is "better" or "right" - I was just expressing that I personally wanted to be able to see some trunk on this tree. There's no reason you couldn't do the same and still work toward a "flame" style.
Thanks! I don't know if this particular tree is one of the common landscape cultivars, or a seedling, or what, but it is unlikely to be a "chi-chi" tree, having come from a basic landscape nursery. I hope you really enjoy yours