The Sark flag has been around in Profile Stats for while. In BadgeGen it is still a broken link, as there was/is no graphic for it. That will change with the update of BadgeGen in the coming weeks: Sark will finally get its own Badge.
Please note that currently Sark has a joined ISO 3166-alpha code with Guernsey (GG), but Project-GC uses the unassigned ZS. Just this week it was announced that Sark got approved for an own ISO code after 20 years. They applied for SQ, so it could be that this will change in the future.