No, synced is a timing thing. All GOUT-synced audio will work with any GOUT-synced video, so people’s lips match up with the words coming out of their mouths, etc. Silver Screen isn’t GOUT-synced, so you are a little more limited in your audio options (or you add dark frames for the missing video to make it GOUT-synced, either way).
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Just to clarify: Star Wars Silver Screen Edition v1.0 is not GOUT sync’d but v1.6 is.