Regardless of whether the email from Create Space came back saying your files meet the requirements for publishing, etc. Get a hard copy.
You will probably find a gazillion little things you need to change. Page numbers to high. Margins not perfect. Chapter headings inconsistent. Font not exactly the size you want. Page breaks not working properly. Things that should be on the front of a page appearing on the reverse side. Images the wrong size or placed badly on the page. And so on. Get a paper copy! And when you think you definitely have it right now, it's time to get another paper copy. Do this until your paper copy is perfect and needs no changes. Then publish.