Dish has had the GSN HD feed since at least 2011.
Recently I've noticed (starting with The Chase's season premiere) that some of GSN's presentational aspects have been modified; namely that on HD shows the logo bug is now 16:9 compliant (all SD shows still have it in the 4:3-safe area), that all 4:3 SD shows except Feud (which is still stretching - with the 4:3-safe bug - for some reason) are now pillarboxed in their proper aspect ratio on the HD feed , and that the SD feed now letterboxes the HD shows and channel promos instead of center-cutting them.