Hi John,
Bas merged my pull request yesterday: https://github.com/bmbrands/theme_bootstrap/pull/347#event-185973445 - so the master branch has been updated. It does not look like they are excluded: https://github.com/thedannywahl/moodle-theme_elegance/blob/master/config.php#L49-L86 - so a 'Purge all caches' should be fine after updating Bootstrap CSS.
Gareth