It's not if a post gets upvotes later, but rather if a moderator or a small number of story reviewers notice that it was a good post that didn't get attention. We've been doing it for quite a while now https://news.ycombinator.com/item?id=11662380. The long term plan is still to open this up to all users, not just a few, but we still haven't figured out a good way to do that.