No, G-Sync doesn't require it because it displays the frames as they finish so there is no reason to have a buffered frame... triple buffering is designed to mask the problems of V-Sync, which G-Sync doesn't have.
GSYNC does frame doubling at low frame rates.
if you drop below 30fps, Gsync will still work.
For example, if your Fps drops to 15 then Gsync will turn refresh rate to 30hz and just double up the frames which works fine.
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