Regarding exporting a GEDCOM from WikiTree and whether you can include sources: Yes, the sources in the text of the page will be included.
The snippet of a WikiTree-exported GEDCOM you show above is a little confusing to parse through. Here's the profile it's from: http://www.wikitree.com/wiki/White-9750
The reason it's showing no sources is that there are no sources on that page, i.e. nothing listed like this: http://www.wikitree.com/wiki/Sources
There's a "== Sources ==" headline and then there are footnotes/references, i.e. http://www.wikitree.com/wiki/Footnotes
The references are actually inline in the biography, which would appear above what you've cut out here. (And be very long, since it's a nice long biography!).
If you're asking whether references can be pulled out of the text during the export process, that would be tricky.
The REFN numbers you see there are separate. You can ignore them. The are just the WikiTree user_id and page_id. Those are things that only a small, small portion of users would ever care about, or we might care about if we're importing a WikiTree-exported file back into WikiTree. If you imported this file into another system they would be ignored.