Yes, it's as castaway says. At the point you are previewing your post, you have not yet created a node, so it can't refer to you and now. The date and owner and you see are that of the preview page, which is much like comment on. I guess the former could be patched to not show an owner and date, like the latter, though I'm not sure (preview page is a strangedoc as opposed to comment on which is a superdoc).