Greetings desertwind
This really depends on what sort of quality you want to pull out of the camera. For showcasing in a theater you will most likely want to use an adapter as you won't loose resolution.
In fact I think the GL2 has an electronic anamorphic mode, yes? That could be an option if you don't want to use an adapter for monetary or creative reasons. In fact using both an adapter and the electronic mode, together, will give you an approximate 2.35:1 ratio - the ratio most DVDs are authored in.