From my experience, anything that sells is covered, regardless of listing date.

However, the account that I get that promo on has little listed since they stopped offering the 3 day unlimited freebies, and most aren't there for long. The first $0 FVF I got with the current promo was listed on 15 Feb. The promo started on 17 Feb.

No guarantees, simply what I have found. As they aren't extra listings, I just list what I normally would and if they sell fee-free, it's a bonus.