The point of using incognito is to be unauthenticated. Otherwise, wouldn't the post always be visible to the submitter, regardless of whether or not it is in the spam filter?

The post will show up for the submitter on their userpage and in their submitted links panel, however it will not show up in the new queue, not even for mods. This may be different for shadowbanned users, but I don't think it is.

Actually, I'm almost certain it's the same for shadowbanned users, because we got two modmail messages today from shadowbanned users asking to have their posts taken out of the spam filter because they can't see them in the new queue.