Yes, of course. We suggest that if you have a book with a strict publication date, you upload it at least two weeks in advance. In this case your book will be automatically set for pre-sale in the stores where this function is available, so your readers can already pre-order your book, but they can read it only after the official publication date set by you in PublishDrive.
At this moment we don't accept assetless pre-orders. Your files, however, don't need to be finalized: we usually recommend uploading a 'dummy' ebook for preorder (e.g. edited first chapter) until your book is ready. You can easily change the actual epub close to the release date without the need of withdrawing the book (we recommend 1-2 weeks in advance to make sure that the updates get processed everywhere).