http://news.ycombinator.com/item?id=1981370
http://news.ycombinator.com/item?id=1986921
http://news.ycombinator.com/item?id=2003817
http://news.ycombinator.com/item?id=2022603
http://news.ycombinator.com/item?id=2629937
http://news.ycombinator.com/item?id=2712978
(Also: I've been on HN for a really long time and there are plenty of things that are months — or years — old that I've forgotten about and wouldn't mind seeing again.)
I think this would only be valuable when the first post is more of a "show hn/looking for contributors" and the second is a "this project has come of age and is valuable for the general population".
Otherwise, if it was valuable then, you would've bookmarked it. If it wasn't, it shouldn't have been submitted.