I ask because, although Wordpress doesn't seem to object when I create a new site, re-using the URL of a deleted site, I don't seem to be able to access its homepage. Trying to do so just generates a 404 and that's probably because..
... gets appended to the URL.
In case it's relevant, my custom permalink structure is...
I am using the directory version of MU, so every site is in a different folder.