I am not aware of a possibility to search for the publication date, especially as very old caches do not have a publication date, including GC21DF, which indeed seems to be the oldest webcam cache. All you can do is look at the "hidden date", which is indeed 11 October 2011 for that cache.
You can get a list using "Map compare": leave the field cache location empty (unless you are interested in a certain area only), add a filter "show disabled/archived" unless you are only interested in active caches. Add a filter "hidden to" if you are interested in certain time (and to prevent the list from getting too long). Add a filter "cache type" if you are interested only in Webcam caches: https://project-gc.com/Tools/MapCompare?profile_name=ivans&nonefound=on&onefound=on&hidden_toyyyy=2001&hidden_tomm=12&hidden_todd=31&type%5B%5D=Webcam+Cache&showdisabled=on&showarchived=on&submit=Filter
Note that strictly speaking the list is ordered by GC-number which is not necessarily the order of "hidden date" but the order according to which the cache page was created. If you want to be absolutely sure about the correct chronological order you would have to check the hidden date for the caches (with GC-numbers close to each other).