If URLs are reverted back to dynamic...

... would they be the same URLs as they were before vBSEO was enabled?

Yes, the URLs would stay they same pre vBSEO. However, your indexed content with the SEO URLs will all be broken links.

If you choose to uninstall, we have a few lines to add to your .htaccess that will redirect all of the vBSEO URLs back to the old format.