I don't think there is a way to find it at the moment. Even though it would be possible to sort caches by publish date, you would not find that precisely, because there are hundreds of new caches published daily, but logs are just saying which day is it, not which time (in most of the cases). PGC has some sense of publish date to select or sort, but it would require listing and sorting of millions of geocaches to get these approximate results. Moreover, it would not reflect the retracted caches, that are never more accessible from web nor from API, but indisputably were published.