I would think so. I tried an experimental import from Wordpress on a "different" server, meaning my root domain and a subdomain, and it worked fine for me. I use Dreamhost, so localhost was not the host for my databases.
OK, thanks, the part I can't figure out is, how the Serendipity importer knows where the old server and Mysql DB is because the importer does not ask for the URL of the old blog.
It should ask you, however, for your WP database host, user, pass, name, and table prefix. It probably won't ask you for the URL, because it won't need it. Just the posts & comments will be imported into your s9y blog.