Doesn't honour style overrides new as of Sketch v52 #13
Description
Not sure whether you're intending to support this in the future, but noticed that the plugin does a perfect job of matching symbol overrides after replacing the symbol instances it currently doesn't seem to support style overrides.
The example I would give would be replacing an icon where some instances have a colour override. The instances are correctly replaced and linked to the new library but loose their Appearance overrides.