They are all 720p. As long as Harmy’s primary source is the 2011 Blu-rays, there’s not much point in doing a higher-res version, since the Blu-rays don’t have any real detail above 720p beyond sharpening artifacts. If someday a better-quality SE release comes out (e.g. the rumored Reliance Media 4K scan), that might open the door to 1080p versions, but the problem is that all the despecialized shots would need to be re-despecialized from scratch–a major undertaking.

In the much more likely scenario that a better-quality fan preservation based on a film scan comes out, Harmy’s been fairly candid that there’s no need to despecialize something that’s not SE to begin with, so he wouldn’t see the need to do anything at all with it. I’d personally see a benefit from mixing in a few extra frames from another source at the reel changes to get it GOUT-synced (and thus have access to all our audio tracks), but a lot more people would be capable of doing that than just Harmy.