Yes exactly. With new parsers or changed, the uploads can be reprocessed to discover new files or update existing archives.
There is an upload download button on the “Your Data” page. But this won’t help you to download the files of others. We could add a “download whole upload” button to the raw files entry page. I don’t think, we can will add it on search results though. Search results might span many uploads and for the user it becomes very hard to ascertain how much data she is trying to download.