Just new ones for now.
I don't want to make HN harder for legit new users, but I do think a bit of community participation is reasonable before posting a Show HN, so it isn't just a box on some "how to promote your project" checklist.
How new is new?
It does seem, anecdotally, that the Show HN is being used less since the recent analytic posts that made it to the front page.
It's really hurting the brand. I can't remember the last time I bothered to even check that index. I used to check it all the time.